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Tolezano GC, Bastos GC, da Costa SS, Scliar MDO, de Souza CFM, Van Der Linden H, Fernandes WLM, Otto PA, Vianna-Morgante AM, Haddad LA, Honjo RS, Yamamoto GL, Kim CA, Rosenberg C, Jorge AADL, Bertola DR, Krepischi ACV. Clinical Characterization and Underlying Genetic Findings in Brazilian Patients with Syndromic Microcephaly Associated with Neurodevelopmental Disorders. Mol Neurobiol 2024; 61:5230-5247. [PMID: 38180615 DOI: 10.1007/s12035-023-03894-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 12/20/2023] [Indexed: 01/06/2024]
Abstract
Microcephaly is characterized by an occipitofrontal circumference at least two standard deviations below the mean for age and sex. Neurodevelopmental disorders (NDD) are commonly associated with microcephaly, due to perturbations in brain development and functioning. Given the extensive genetic heterogeneity of microcephaly, managing patients is hindered by the broad spectrum of diagnostic possibilities that exist before conducting molecular testing. We investigated the genetic basis of syndromic microcephaly accompanied by NDD in a Brazilian cohort of 45 individuals and characterized associated clinical features, as well as evaluated the effectiveness of whole-exome sequencing (WES) as a diagnostic tool for this condition. Patients previously negative for pathogenic copy number variants underwent WES, which was performed using a trio approach for isolated index cases (n = 31), only the index in isolated cases with parental consanguinity (n = 8) or affected siblings in familial cases (n = 3). Pathogenic/likely pathogenic variants were identified in 19 families (18 genes) with a diagnostic yield of approximately 45%. Nearly 86% of the individuals had global developmental delay/intellectual disability and 51% presented with behavioral disturbances. Additional frequent clinical features included facial dysmorphisms (80%), brain malformations (67%), musculoskeletal (71%) or cardiovascular (47%) defects, and short stature (54%). Our findings unraveled the underlying genetic basis of microcephaly in half of the patients, demonstrating a high diagnostic yield of WES for microcephaly and reinforcing its genetic heterogeneity. We expanded the phenotypic spectrum associated with the condition and identified a potentially novel gene (CCDC17) for congenital microcephaly.
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Affiliation(s)
- Giovanna Cantini Tolezano
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, Human Genome and Stem-Cell Research Center, University of São Paulo, 277 Rua do Matão, São Paulo, SP, 05508-090, Brazil
| | - Giovanna Civitate Bastos
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, Human Genome and Stem-Cell Research Center, University of São Paulo, 277 Rua do Matão, São Paulo, SP, 05508-090, Brazil
| | - Silvia Souza da Costa
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, Human Genome and Stem-Cell Research Center, University of São Paulo, 277 Rua do Matão, São Paulo, SP, 05508-090, Brazil
| | - Marília de Oliveira Scliar
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, Human Genome and Stem-Cell Research Center, University of São Paulo, 277 Rua do Matão, São Paulo, SP, 05508-090, Brazil
| | - Carolina Fischinger Moura de Souza
- Postgraduate Program in Child and Adolescent Health, Universidade Federal do Rio Grande do Sul, Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | | | | | - Paulo Alberto Otto
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, SP, Brazil
| | - Angela M Vianna-Morgante
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, Human Genome and Stem-Cell Research Center, University of São Paulo, 277 Rua do Matão, São Paulo, SP, 05508-090, Brazil
| | - Luciana Amaral Haddad
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, SP, Brazil
| | - Rachel Sayuri Honjo
- Unidade de Genética do Instituto da Criança, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
| | - Guilherme Lopes Yamamoto
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, Human Genome and Stem-Cell Research Center, University of São Paulo, 277 Rua do Matão, São Paulo, SP, 05508-090, Brazil
- Unidade de Genética do Instituto da Criança, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
| | - Chong Ae Kim
- Unidade de Genética do Instituto da Criança, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
| | - Carla Rosenberg
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, Human Genome and Stem-Cell Research Center, University of São Paulo, 277 Rua do Matão, São Paulo, SP, 05508-090, Brazil
| | - Alexander Augusto de Lima Jorge
- Unidade de Endocrinologia Genética (LIM25), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
| | - Débora Romeo Bertola
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, Human Genome and Stem-Cell Research Center, University of São Paulo, 277 Rua do Matão, São Paulo, SP, 05508-090, Brazil
- Unidade de Genética do Instituto da Criança, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
| | - Ana Cristina Victorino Krepischi
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, Human Genome and Stem-Cell Research Center, University of São Paulo, 277 Rua do Matão, São Paulo, SP, 05508-090, Brazil.
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Lara MK, Brabec JL, Hernan AE, Scott RC, Tyler AL, Mahoney JM. Network-based analysis predicts interacting genetic modifiers from a meta-mapping study of spike-wave discharge in mice. GENES, BRAIN, AND BEHAVIOR 2024; 23:e12879. [PMID: 38444174 PMCID: PMC10915378 DOI: 10.1111/gbb.12879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 11/29/2023] [Accepted: 12/19/2023] [Indexed: 03/07/2024]
Abstract
Absence seizures are characterized by brief lapses in awareness accompanied by a hallmark spike-and-wave discharge (SWD) electroencephalographic pattern and are common to genetic generalized epilepsies (GGEs). While numerous genes have been associated with increased risk, including some Mendelian forms with a single causal allele, most cases of GGE are idiopathic and there are many unknown genetic modifiers of GGE influencing risk and severity. In a previous meta-mapping study, crosses between transgenic C57BL/6 and C3HeB/FeJ strains, each carrying one of three SWD-causing mutations (Gabrg2tm1Spet(R43Q) , Scn8a8j or Gria4spkw1 ), demonstrated an antagonistic epistatic interaction between loci on mouse chromosomes 2 and 7 influencing SWD. These results implicate universal modifiers in the B6 background that mitigate SWD severity through a common pathway, independent of the causal mutation. In this study, we prioritized candidate modifiers in these interacting loci. Our approach integrated human genome-wide association results with gene interaction networks and mouse brain gene expression to prioritize candidate genes and pathways driving variation in SWD outcomes. We considered candidate genes that are functionally associated with human GGE risk genes and genes with evidence for coding or non-coding allele effects between the B6 and C3H backgrounds. Our analyses output a summary ranking of gene pairs, one gene from each locus, as candidates for explaining the epistatic interaction. Our top-ranking gene pairs implicate microtubule function, cytoskeletal stability and cell cycle regulation as novel hypotheses about the source of SWD variation across strain backgrounds, which could clarify underlying mechanisms driving differences in GGE severity in humans.
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Affiliation(s)
- Montana Kay Lara
- Department of Neurological SciencesUniversity of VermontBurlingtonVermontUSA
| | - Jeffrey L. Brabec
- Department of Neurological SciencesUniversity of VermontBurlingtonVermontUSA
| | - Amanda E. Hernan
- Department of Neurological SciencesUniversity of VermontBurlingtonVermontUSA
- Division of NeuroscienceNemours Children's HealthWilmingtonDelawareUSA
- Department of Psychological and Brain SciencesUniversity of DelawareNewarkDelawareUSA
| | - Rod C. Scott
- Division of NeuroscienceNemours Children's HealthWilmingtonDelawareUSA
- Department of Psychological and Brain SciencesUniversity of DelawareNewarkDelawareUSA
| | | | - J. Matthew Mahoney
- Department of Neurological SciencesUniversity of VermontBurlingtonVermontUSA
- The Jackson LaboratoryBar HarborMaineUSA
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Zhou Y, Xu MF, Chen J, Zhang JL, Wang XY, Huang MH, Wei YL, She ZY. Loss-of-function of kinesin-5 KIF11 causes microcephaly, chorioretinopathy, and developmental disorders through chromosome instability and cell cycle arrest. Exp Cell Res 2024; 436:113975. [PMID: 38367657 DOI: 10.1016/j.yexcr.2024.113975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/02/2024] [Accepted: 02/12/2024] [Indexed: 02/19/2024]
Abstract
Kinesin motors play a fundamental role in development by controlling intracellular transport, spindle assembly, and microtubule organization. In humans, patients carrying mutations in KIF11 suffer from an autosomal dominant inheritable disease called microcephaly with or without chorioretinopathy, lymphoedema, or mental retardation (MCLMR). While mitotic functions of KIF11 proteins have been well documented in centrosome separation and spindle assembly, cellular mechanisms underlying KIF11 dysfunction and MCLMR remain unclear. In this study, we generate KIF11-inhibition chick and zebrafish models and find that KIF11 inhibition results in microcephaly, chorioretinopathy, and severe developmental defects in vivo. Notably, loss-of-function of KIF11 causes the formation of monopolar spindle and chromosome misalignment, which finally contribute to cell cycle arrest, chromosome instability, and cell death. Our results demonstrate that KIF11 is crucial for spindle assembly, chromosome alignment, and cell cycle progression of progenitor stem cells, indicating a potential link between polyploidy and MCLMR. Our data have revealed that KIF11 inhibition cause microcephaly, chorioretinopathy, and development disorders through the formation of monopolar spindle, polyploid, and cell cycle arrest.
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Affiliation(s)
- Yi Zhou
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, 350122, China; Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, Fuzhou, Fujian, 350122, China
| | - Meng-Fei Xu
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, 350122, China; Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, Fuzhou, Fujian, 350122, China
| | - Jie Chen
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, 350122, China; Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, Fuzhou, Fujian, 350122, China
| | - Jing-Lian Zhang
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, 350122, China; Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, Fuzhou, Fujian, 350122, China
| | - Xin-Yao Wang
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, 350122, China; Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, Fuzhou, Fujian, 350122, China
| | - Min-Hui Huang
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, 350122, China; Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, Fuzhou, Fujian, 350122, China
| | - Ya-Lan Wei
- Medical Research Center, Fujian Maternity and Child Health Hospital, Fuzhou, Fujian, 350001, China; College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, Fujian, 350122, China
| | - Zhen-Yu She
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, 350122, China; Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, Fuzhou, Fujian, 350122, China.
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Yahalom C, Woods RL, Akula JD, Tan WH, Fulton A. Microcephaly and chorioretinopathy associated with TUBGCP4: a case report and a review of the literature. Ophthalmic Genet 2023; 44:585-590. [PMID: 37038737 DOI: 10.1080/13816810.2023.2170424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 01/05/2023] [Accepted: 01/15/2023] [Indexed: 04/12/2023]
Abstract
BACKGROUND Microcephaly and chorioretinopathy (MCCRP) is a rare autosomal recessive (AR) disorder characterized by microcephaly, developmental delay, chorioretinopathy, and visual impairment. We characterized the long-term phenotype of an additional patient with MCCRP associated with TUBCGP4 pathogenic variants and analysed previously reported cases in the literature. MATERIALS AND METHODS Analysis of clinical and genetic data of a patient with TUBGCP4-related MCCRP followed for more than 19 years and literature search for previously reported patients with TUBCGP4 variants using PubMed, Scopus, and Google Scholar. RESULTS Molecular diagnosis using exome sequencing demonstrated two TUBCGP4 variants in trans: c.1669C>T (p.Arg557*) and c.1746 G>T (p.Leu582=). Clinical characteristics included microcephaly, microphthalmia, punched-out chorioretinal lesions, vision impairment, nystagmus, Tetralogy of Fallot and neurodevelopmental delay. Another six previously reported cases of TUBCGP4-related MCCRP were identified. Their clinical and genetic characteristics are compared. CONCLUSIONS TUBCGP4-related microcephaly and chorioretinopathy, is a rare autosomal recessive neuro-ophthalmic disorder. Clinical characteristics in our proband have remained stable for two decades. The pathophysiology of this syndrome is not yet fully understood.
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Affiliation(s)
- Claudia Yahalom
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Russell L Woods
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - James D Akula
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Wen-Hann Tan
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Anne Fulton
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Ramesh Babu PB. Prediction of anti-microtubular target proteins of tubulins and their interacting proteins using Gene Ontology tools. J Genet Eng Biotechnol 2023; 21:78. [PMID: 37466845 DOI: 10.1186/s43141-023-00531-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 07/01/2023] [Indexed: 07/20/2023]
Abstract
BACKGROUND Tubulins are highly conserved globular proteins involved in stabilization of cellular cytoskeletal microtubules during cell cycle. Different isoforms of tubulins are differentially expressed in various cell types, and their protein-protein interactions (PPIs) analysis will help in identifying the anti-microtubular drug targets for cancer and neurological disorders. Numerous web-based PPIs analysis methods are recently being used, and in this paper, I used Gene Ontology (GO) tools, e.g., Stringbase, ProteomeHD, GeneMANIA, and ShinyGO, to identify anti-microtubular target proteins by selecting strongly interacting proteins of tubulins. RESULTS I used 6 different human tubulin isoforms (two from each of α-, β-, and γ-tubulin) and found several thousands of node-to-node protein interactions (highest 4956 in GeneMANIA) and selected top 10 strongly interacting node-to-node interactions with highest score, which included 7 tubulin family protein and 6 non-tubulin family proteins (total 13). Functional enrichment analysis indicated a significant role of these 13 proteins in nucleation, polymerization or depolymerization of microtubules, membrane tethering and docking, dorsal root ganglion development, mitotic cycle, and cytoskeletal organization. I found γ-tubulins (TUBG1, TUBGCP4, and TUBBGCP6) were known to contribute majorly for tubulin-associated functions followed by α-tubulin (TUBA1A) and β-tubulins (TUBB AND TUBB3). In PPI results, I found several non-tubular proteins interacting with tubulins, and six of them (HTT, DPYSL2, SKI, UNC5C, NINL, and DDX41) were found closely associated with their functions. CONCLUSIONS Increasing number of regulatory proteins and subpopulation of tubulin proteins are being reported with poor understanding in their association with microtubule assembly and disassembly. The functional enrichment analysis of tubulin isoforms using recent GO tools resulted in identification of γ-tubulins playing a key role in microtubule functions and observed non-tubulin family of proteins HTT, DPYSL2, SKI, UNC5C, NINL, and DDX41 strongly interacting functional proteins of tubulins. The present study yields a promising model system using GO tools to narrow down tubulin-associated proteins as a drug target in cancer, Alzheimer's, neurological disorders, etc.
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Affiliation(s)
- Polani B Ramesh Babu
- Center for Materials Engineering and Regenerative Medicine, Bharath Institute of Higher Education and Research, Bharath Institute of Science and Technology, Selaiyur, Tambaram, Chennai, India.
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Farcy S, Hachour H, Bahi-Buisson N, Passemard S. Genetic Primary Microcephalies: When Centrosome Dysfunction Dictates Brain and Body Size. Cells 2023; 12:1807. [PMID: 37443841 PMCID: PMC10340463 DOI: 10.3390/cells12131807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 06/04/2023] [Accepted: 06/13/2023] [Indexed: 07/15/2023] Open
Abstract
Primary microcephalies (PMs) are defects in brain growth that are detectable at or before birth and are responsible for neurodevelopmental disorders. Most are caused by biallelic or, more rarely, dominant mutations in one of the likely hundreds of genes encoding PM proteins, i.e., ubiquitous centrosome or microtubule-associated proteins required for the division of neural progenitor cells in the embryonic brain. Here, we provide an overview of the different types of PMs, i.e., isolated PMs with or without malformations of cortical development and PMs associated with short stature (microcephalic dwarfism) or sensorineural disorders. We present an overview of the genetic, developmental, neurological, and cognitive aspects characterizing the most representative PMs. The analysis of phenotypic similarities and differences among patients has led scientists to elucidate the roles of these PM proteins in humans. Phenotypic similarities indicate possible redundant functions of a few of these proteins, such as ASPM and WDR62, which play roles only in determining brain size and structure. However, the protein pericentrin (PCNT) is equally required for determining brain and body size. Other PM proteins perform both functions, albeit to different degrees. Finally, by comparing phenotypes, we considered the interrelationships among these proteins.
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Affiliation(s)
- Sarah Farcy
- UMR144, Institut Curie, 75005 Paris, France;
- Inserm UMR-S 1163, Institut Imagine, 75015 Paris, France
| | - Hassina Hachour
- Service de Neurologie Pédiatrique, DMU INOV-RDB, APHP, Hôpital Robert Debré, 75019 Paris, France;
| | - Nadia Bahi-Buisson
- Service de Neurologie Pédiatrique, DMU MICADO, APHP, Hôpital Necker Enfants Malades, 75015 Paris, France;
- Université Paris Cité, Inserm UMR-S 1163, Institut Imagine, 75015 Paris, France
| | - Sandrine Passemard
- Service de Neurologie Pédiatrique, DMU INOV-RDB, APHP, Hôpital Robert Debré, 75019 Paris, France;
- Université Paris Cité, Inserm UMR 1141, NeuroDiderot, 75019 Paris, France
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7
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Sengillo JD, Ashkenazy N, Shoji MK, Iyer P, Robles-Holmes HK, Lopez A, Yannuzzi NA, Negron CI, Berrocal AM. Familial Exudative Vitreoretinopathy-Like Phenotype in a Patient With Microcephaly and TUBGCP6 Mutations. JOURNAL OF VITREORETINAL DISEASES 2023; 7:344-347. [PMID: 37927319 PMCID: PMC10621710 DOI: 10.1177/24741264231167236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Purpose: To describe a case of microcephaly, unilateral retinal fold, and familial exudative vitreoretinopathy (FEVR)-like phenotype in the context of 2 TUBGCP6 variants. Methods: A case and its findings were analyzed. Results: A 4-month-old boy with no family history of eye disease presented by referral for management of presumed persistent fetal vasculature in the left eye. An external examination showed microcephaly. The patient grimaced to light in both eyes, and the anterior segments were unremarkable. On dilated fundus examination, diffuse chorioretinal atrophy was present bilaterally. In the left eye, a retinal fold emanated from the optic nerve head. There was early termination of retinal vasculature, especially in zone 3 in the left eye, resembling a FEVR-like phenotype. Panel-based genetic testing was performed and found 2 mutations in TUBGCP6. Conclusions: Microcephaly, chorioretinopathy, and retinal folds may be associated with TUBGCP6 mutations and masquerade as PFV.
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Affiliation(s)
- Jesse D. Sengillo
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Noy Ashkenazy
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Marissa K. Shoji
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Prashanth Iyer
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Hailey K. Robles-Holmes
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Ashley Lopez
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Nicolas A. Yannuzzi
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Catherin I. Negron
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Audina M. Berrocal
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
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Biswal SR, Singh M, Dwibedy SLL, Kumari S, Muthuswamy S, Kumar A, Kumar S. Deciphering the RNA-binding protein interaction with the mRNAs encoded from human chromosome 15q11.2 BP1-BP2 microdeletion region. Funct Integr Genomics 2023; 23:174. [PMID: 37219715 DOI: 10.1007/s10142-023-01105-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/12/2023] [Accepted: 05/15/2023] [Indexed: 05/24/2023]
Abstract
Microdeletion of the 15q11.2 BP1-BP2 region, also known as Burnside-Butler susceptibility region, is associated with phenotypes like delayed developmental language abilities along with motor skill disabilities, combined with behavioral and emotional problems. The 15q11.2 microdeletion region harbors four evolutionarily conserved and non-imprinted protein-coding genes: NIPA1, NIPA2, CYFIP1, and TUBGCP5. This microdeletion is a rare copy number variation frequently associated with several pathogenic conditions in humans. The aim of this study is to investigate the RNA-binding proteins binding with the four genes present in 15q11.2 BP1-BP2 microdeletion region. The results of this study will help to better understand the molecular intricacies of the Burnside-Butler Syndrome and also the possible involvement of these interactions in the disease aetiology. Our results of enhanced crosslinking and immunoprecipitation data analysis indicate that most of the RBPs interacting with the 15q11.2 region are involved in the post-transcriptional regulation of the concerned genes. The RBPs binding to this region are found from the in silico analysis, and the interaction of RBPs like FASTKD2 and EFTUD2 with exon-intron junction sequence of CYFIP1 and TUBGCP5 has also been validated by combined EMSA and western blotting experiment. The exon-intron junction binding nature of these proteins suggests their potential involvement in splicing process. This study may help to understand the intricate relationship of RBPs with mRNAs within this region, along with their functional significance in normal development, and lack thereof, in neurodevelopmental disorders. This understanding will help in the formulation of better therapeutic approaches.
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Affiliation(s)
- Smruti Rekha Biswal
- Department of Life Science, National Institute of Technology (NIT), Rourkela, Odisha, 769008, India
| | - Mandakini Singh
- Department of Life Science, National Institute of Technology (NIT), Rourkela, Odisha, 769008, India
| | | | - Subhadra Kumari
- Department of Life Science, National Institute of Technology (NIT), Rourkela, Odisha, 769008, India
| | - Srinivasan Muthuswamy
- Department of Life Science, National Institute of Technology (NIT), Rourkela, Odisha, 769008, India
| | - Ajay Kumar
- Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, 221005, India
| | - Santosh Kumar
- Department of Life Science, National Institute of Technology (NIT), Rourkela, Odisha, 769008, India.
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9
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Thomas-Wilson A, Schacht JP, Chitayat D, Blaser S, Santos FJR, Glaser K, Caffo A, Wentzensen IM, Henderson LB, Zhang F, Zhu Y, Di Corleto E, da Silva Costa F, Vink R, Alkhunaizi E, Russell L, Buckley MF, Roscioli T, Pereira EM, Ganapathi M. Biallelic variants in TUBGCP6 result in microcephaly and chorioretinopathy 1: Report of four cases and a literature review. Am J Med Genet A 2023. [PMID: 37031378 DOI: 10.1002/ajmg.a.63203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 04/10/2023]
Abstract
Autosomal recessive microcephaly and chorioretinopathy-1 (MCCRP1) is a rare Mendelian disorder resulting from biallelic loss of function variants in Tubulin-Gamma Complex Associated Protein 6 (TUBGCP6, MIM#610053). Clinical features of this disorder include microcephaly, cognitive impairment, dysmorphic features, and variable ophthalmological anomalies including chorioretinopathy. Microcephaly can be recognized prenatally and visual impairment becomes evident during the first year of life. The clinical presentation resembles the findings in some acquired conditions such as congenital toxoplasmosis and cytomegalovirus infections; thus, it is important to recognize and diagnose this syndrome in view of its impact on patient health management and familial reproductive plans. To date, only seven molecularly confirmed patients from five unrelated families have been reported. We report an additional four unrelated patients with TUBGCP6 variants including one prenatal diagnosis and review the clinical phenotypes and genotypes of all the known cases. This report expands the molecular and phenotypic spectrum of TUBGCP6 and includes additional prenatal findings associated with MCCRP1.
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Affiliation(s)
- Amanda Thomas-Wilson
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, New York, USA
| | - John P Schacht
- Department of Pediatrics, Division of Clinical Genetics, Columbia University Irving Medical Center, New York, New York, USA
| | - David Chitayat
- Department of Pediatrics, Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
- The Prenatal Diagnosis and Medical Genetics Program, Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Susan Blaser
- Department of Diagnostic Imaging, Division of Pediatric Neuroradiology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | | | - Kimberly Glaser
- Department of Clinical Genetics, Joe DiMaggio Children's Hospital, Hollywood, Florida, USA
| | - Alesky Caffo
- Department of Clinical Genetics, Joe DiMaggio Children's Hospital, Hollywood, Florida, USA
| | | | | | - Futao Zhang
- New South Wales Health Pathology, Randwick Genomics Laboratory, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Ying Zhu
- New South Wales Health Pathology, Randwick Genomics Laboratory, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Ellen Di Corleto
- Maternal Fetal Medicine Unit, Gold Coast University Hospital, Gold Coast, Queensland, Australia
| | - Fabricio da Silva Costa
- Maternal Fetal Medicine Unit, Gold Coast University Hospital, Gold Coast, Queensland, Australia
- School of Medicine and Dentistry, Griffith University, Gold Coast, Queensland, Australia
| | - Rebecca Vink
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- Centre for Clinical Genetics, Sydney Children's Hospital, Sydney, New South Wales, Australia
| | - Ebba Alkhunaizi
- Department of Pediatrics, Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Genetics, McGill University Health Centre, Montreal, Quebec, Canada
| | - Laura Russell
- Department of Medical Genetics, McGill University Health Centre, Montreal, Quebec, Canada
| | - Michael F Buckley
- New South Wales Health Pathology, Randwick Genomics Laboratory, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Tony Roscioli
- New South Wales Health Pathology, Randwick Genomics Laboratory, Prince of Wales Hospital, Sydney, New South Wales, Australia
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- Prince of Wales Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Elaine Maria Pereira
- Department of Pediatrics, Division of Clinical Genetics, Columbia University Irving Medical Center, New York, New York, USA
| | - Mythily Ganapathi
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, New York, USA
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10
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Cardozo MJ, Sánchez-Bustamante E, Bovolenta P. Optic cup morphogenesis across species and related inborn human eye defects. Development 2023; 150:286775. [PMID: 36714981 PMCID: PMC10110496 DOI: 10.1242/dev.200399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The vertebrate eye is shaped as a cup, a conformation that optimizes vision and is acquired early in development through a process known as optic cup morphogenesis. Imaging living, transparent teleost embryos and mammalian stem cell-derived organoids has provided insights into the rearrangements that eye progenitors undergo to adopt such a shape. Molecular and pharmacological interference with these rearrangements has further identified the underlying molecular machineries and the physical forces involved in this morphogenetic process. In this Review, we summarize the resulting scenarios and proposed models that include common and species-specific events. We further discuss how these studies and those in environmentally adapted blind species may shed light on human inborn eye malformations that result from failures in optic cup morphogenesis, including microphthalmia, anophthalmia and coloboma.
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Affiliation(s)
- Marcos J Cardozo
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, c/ Nicolás Cabrera 1, Cantoblanco, Madrid 28049, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), c/ Nicolás Cabrera 1, Cantoblanco, Madrid 28049, Spain
| | - Elena Sánchez-Bustamante
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, c/ Nicolás Cabrera 1, Cantoblanco, Madrid 28049, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), c/ Nicolás Cabrera 1, Cantoblanco, Madrid 28049, Spain
| | - Paola Bovolenta
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, c/ Nicolás Cabrera 1, Cantoblanco, Madrid 28049, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), c/ Nicolás Cabrera 1, Cantoblanco, Madrid 28049, Spain
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11
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Clinical Significance of TUBGCP4 Expression in Hepatocellular Carcinoma. Anal Cell Pathol (Amst) 2022; 2022:9307468. [DOI: 10.1155/2022/9307468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 11/06/2022] [Accepted: 11/21/2022] [Indexed: 12/13/2022] Open
Abstract
We aim to investigate the expression and clinical significance of the tubulin gamma complex-associated protein 4 (TUBGCP4) in hepatocellular carcinoma (HCC). The mRNA expression of TUBGCP4 in HCC tissues was analyzed using The Cancer Genome Atlas (TCGA) database. Paired HCC and adjacent nontumor tissues were obtained from HCC patients to measure the protein expression of TUBGCP4 by immunohistochemistry (IHC) and to analyze the relationship between TUBGCP4 protein expression and the clinicopathological characteristics and the prognosis of HCC patients. We found that TUBGCP4 mRNA expression was upregulated in HCC tissues from TCGA database. IHC analysis showed that TUBGCP4 was positively expressed in 61.25% (49/80) of HCC tissues and 77.5% (62/80) of adjacent nontumor tissues. The Chi-square analysis indicated that the positive rate of TUBGCP4 expression between HCC tissues and the adjacent nontumor tissues was statistically different (
). Furthermore, we found that TUBGCP4 protein expression was correlated with carbohydrate antigen (CA-199) levels of HCC patients (
). Further, survival analysis showed that the overall survival time and tumor-free survival time in the TUBGCP4 positive group were significantly higher than those of the negative group (
), indicating that the positive expression of TUBGCP4 was related to a better prognosis of HCC patients. COX model showed that TUBGCP4 was an independent prognostic factor for HCC patients. Our study indicates that TUBGCP4 protein expression is downregulated in HCC tissues and has a relationship with the prognosis of HCC patients.
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12
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Martín-Rivada Á, Pozo-Román J, Güemes M, Ortiz-Cabrera NV, Pérez-Jurado LA, Argente J. Primary Dwarfism, Microcephaly, and Chorioretinopathy due to a PLK4 Mutation in Two Siblings. Horm Res Paediatr 2022; 93:567-572. [PMID: 33756487 DOI: 10.1159/000514280] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/07/2021] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Primary autosomal recessive microcephalies (MCPHs) are characterized by primary dwarfism with MCPH and may present delayed psychomotor development and visual impairment. Biallelic loss of function variants in the PLK4 gene, which encodes the polo-like kinase 4 protein involved in centriole biogenesis, has been recently identified in several patients with MCPH and various ethnic backgrounds. CASE PRESENTATION Here, we describe 2 siblings of different sex from Equatorial Guinea harboring a homozygous frameshift mutation in PLK4 (c.1299_1303del, p.Phe433Leufs*6). A Seckel syndrome spectrum phenotype was present in both siblings, with short stature, severe MCPH, reduced brain volume, and distinctive facial features. They also presented severe intellectual disability, lissencephaly/pachygyria, subependymal heterotopia, and ophthalmological impairment. One of them suffered from deafness, and scoliosis was observed in the other. DISCUSSION/CONCLUSION Biallelic variants in PLK4 lead to a syndrome where severe short stature, MCPH, and cognitive impairment are constant features. However, ocular, skeletal, and other neurological manifestations can vary upon the same genetic basis.
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Affiliation(s)
- Álvaro Martín-Rivada
- Departments of Pediatrics & Pediatric Endocrinology, Hospital Infantil Universitario Niño Jesús, Research Institute "La Princesa,", Madrid, Spain
| | - Jesús Pozo-Román
- Departments of Pediatrics & Pediatric Endocrinology, Hospital Infantil Universitario Niño Jesús, Research Institute "La Princesa,", Madrid, Spain.,Department of Pediatrics, Universidad Autónoma de Madrid, Madrid, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutriciόn (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - María Güemes
- Departments of Pediatrics & Pediatric Endocrinology, Hospital Infantil Universitario Niño Jesús, Research Institute "La Princesa,", Madrid, Spain
| | | | - Luis A Pérez-Jurado
- Genetics Unit, Universitat Pompeu Fabra, Barcelona, Spain.,Hospital del Mar Research Institute (IMIM), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain.,Women's and Children's Hospital, South Australian Health and Medical Research Institute (SAHMRI), The University of Adelaide, Adelaide, South Australia, Australia
| | - Jesús Argente
- Departments of Pediatrics & Pediatric Endocrinology, Hospital Infantil Universitario Niño Jesús, Research Institute "La Princesa,", Madrid, Spain, .,Department of Pediatrics, Universidad Autónoma de Madrid, Madrid, Spain, .,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutriciόn (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain, .,IMDEA, Food Institute, CEIUAM+CSI, Cantoblanco, Madrid, Spain,
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13
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Martín Fernández-Mayoralas D, Albert J, López-Martín S, de la Peña MJ, Fernández-Perrone AL, Jiménez de Domingo A, Calleja-Pérez B, Martínez-García M, Álvarez S, Fernández-Jaén A. Bi-Allelic c.1746G>T; p.Leu582= Variants in TUBGCP4 in a Boy with Autism: Clinical Data and Literature Review. Mol Syndromol 2022; 13:165-170. [PMID: 35418825 PMCID: PMC8928183 DOI: 10.1159/000519365] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 08/31/2021] [Indexed: 02/12/2024] Open
Abstract
Bi-allelic mutations in the TUBGCP4 gene have been recently associated with autosomal recessive microcephaly with chorioretinopathy. However, little is known about the genotype-phenotype characteristics of this disorder. Here, we describe a 5-year-old male patient with autism and a normal occipitofrontal circumference. No retinal abnormalities were observed. Brain MRI revealed the presence of enlarged sheaths of both tortuous optic nerves; both eyes had shorter axial lengths. Whole-exome sequencing in trio revealed synonymous TUBGCP4 variants in homozygous state: c.1746G>T; p.Leu582=. This synonymous variant has been previously described and probably leads to skipping of exon 16 of TUBGCP4. These results broaden the clinical spectrum of this new syndrome and suggest that TUBGCP4 bi-allelic mutations may underlie complex neurodevelopmental disorders.
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Affiliation(s)
| | - Jacobo Albert
- Faculty of Psychology, Universidad Autónoma de Madrid, Madrid, Spain
| | - Sara López-Martín
- Faculty of Psychology, Universidad Autónoma de Madrid, Madrid, Spain
- Neuromottiva, Madrid, Spain
| | | | | | | | | | | | - Sara Álvarez
- Genomics and Medicine, NIMGenetics, Madrid, Spain
| | - Alberto Fernández-Jaén
- Department of Pediatric Neurology, Hospital Universitario Quirónsalud, Madrid, Spain
- School of Medicine, Universidad Europea de Madrid, Madrid, Spain
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14
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Abstract
In this review, Phan et al. discuss the different models that have been proposed to explain how centrosome dysfunction impairs cortical development, and review the evidence supporting a unified model in which centrosome defects reduce cell proliferation in the developing cortex by prolonging mitosis and activating a mitotic surveillance pathway. Last, they also extend their discussion to centrosome-independent microcephaly mutations, such as those involved in DNA replication and repair Primary microcephaly is a brain growth disorder characterized by a severe reduction of brain size and thinning of the cerebral cortex. Many primary microcephaly mutations occur in genes that encode centrosome proteins, highlighting an important role for centrosomes in cortical development. Centrosomes are microtubule organizing centers that participate in several processes, including controlling polarity, catalyzing spindle assembly in mitosis, and building primary cilia. Understanding which of these processes are altered and how these disruptions contribute to microcephaly pathogenesis is a central unresolved question. In this review, we revisit the different models that have been proposed to explain how centrosome dysfunction impairs cortical development. We review the evidence supporting a unified model in which centrosome defects reduce cell proliferation in the developing cortex by prolonging mitosis and activating a mitotic surveillance pathway. Finally, we also extend our discussion to centrosome-independent microcephaly mutations, such as those involved in DNA replication and repair.
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15
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Schweizer N, Haren L, Dutto I, Viais R, Lacasa C, Merdes A, Lüders J. Sub-centrosomal mapping identifies augmin-γTuRC as part of a centriole-stabilizing scaffold. Nat Commun 2021; 12:6042. [PMID: 34654813 PMCID: PMC8519919 DOI: 10.1038/s41467-021-26252-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 09/22/2021] [Indexed: 11/08/2022] Open
Abstract
Centriole biogenesis and maintenance are crucial for cells to generate cilia and assemble centrosomes that function as microtubule organizing centers (MTOCs). Centriole biogenesis and MTOC function both require the microtubule nucleator γ-tubulin ring complex (γTuRC). It is widely accepted that γTuRC nucleates microtubules from the pericentriolar material that is associated with the proximal part of centrioles. However, γTuRC also localizes more distally and in the centriole lumen, but the significance of these findings is unclear. Here we identify spatially and functionally distinct subpopulations of centrosomal γTuRC. Luminal localization is mediated by augmin, which is linked to the centriole inner scaffold through POC5. Disruption of luminal localization impairs centriole integrity and interferes with cilium assembly. Defective ciliogenesis is also observed in γTuRC mutant fibroblasts from a patient suffering from microcephaly with chorioretinopathy. These results identify a non-canonical role of augmin-γTuRC in the centriole lumen that is linked to human disease.
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Affiliation(s)
- Nina Schweizer
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), 08028, Barcelona, Spain
| | - Laurence Haren
- Molecular, Cellular and Developmental Biology, Centre de Biologie Intégrative, CNRS-Université Toulouse III, 31062, Toulouse, France
| | - Ilaria Dutto
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), 08028, Barcelona, Spain
| | - Ricardo Viais
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), 08028, Barcelona, Spain
| | - Cristina Lacasa
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), 08028, Barcelona, Spain
| | - Andreas Merdes
- Molecular, Cellular and Developmental Biology, Centre de Biologie Intégrative, CNRS-Université Toulouse III, 31062, Toulouse, France
| | - Jens Lüders
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), 08028, Barcelona, Spain.
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16
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Abstract
Centrioles are microtubule-based cylindrical structures that assemble the centrosome and template the formation of cilia. The proximal part of centrioles is associated with the pericentriolar material, a protein scaffold from which microtubules are nucleated. This activity is mediated by the γ-tubulin ring complex (γTuRC) whose central role in centrosomal microtubule organization has been recognized for decades. However, accumulating evidence suggests that γTuRC activity at this organelle is neither restricted to the pericentriolar material nor limited to microtubule nucleation. Instead, γTuRC is found along the entire centriole cylinder, at subdistal appendages, and inside the centriole lumen, where its canonical function as a microtubule nucleator might be supplemented or replaced by a function in microtubule anchoring and centriole stabilization, respectively. In this Opinion, we discuss recent insights into the expanded repertoire of γTuRC activities at centrioles and how distinct subpopulations of γTuRC might act in concert to ensure centrosome and cilia biogenesis and function, ultimately supporting cell proliferation, differentiation and homeostasis. We propose that the classical view of centrosomal γTuRC as a pericentriolar material-associated microtubule nucleator needs to be revised.
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Affiliation(s)
- Nina Schweizer
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Jens Lüders
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, 08028 Barcelona, Spain
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17
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Overexpression of the PLK4 Gene as a Novel Strategy for the Treatment of Autosomal Recessive Microcephaly by Improving Centrosomal Dysfunction. J Mol Neurosci 2021; 71:2618-2627. [PMID: 34272646 DOI: 10.1007/s12031-021-01881-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 06/21/2021] [Indexed: 01/19/2023]
Abstract
Autosomal recessive microcephaly and chorioretinopathy (MCCRP) is a neurodevelopmental disorder characterized by delayed psychomotor development, growth retardation with dwarfism, and ocular abnormalities, and its occurrence has been found to be closely related to variants of the gene encoding centrosomes. However, the association between centrosomal duplication defects and the etiology of microcephaly syndromes is poorly understood. It is well known that polo-like kinase 4 (PLK4) is a key regulator of centriole duplication, and the abnormalities of centrosomal function caused by its protein variation need to be further explored in the pathogenesis of microcephaly. In our study, we found that a patient with microcephaly and chorioretinopathy harbored compound heterozygous missense variants NM_014264.4: c.2221C > T (p.Gln741*) and NM_014264.4: c.2062 T > C (p.Tyr688His) in the PLK4 gene. Overexpression experiments of the variant PLK4 proteins then showed that the G741 variant rather than the T688H variant had lost centrosomal amplification ability, and the G741 variant but not the T688H variant induced centrosomal replication disorder, which further inhibited cell proliferation, cycle division and cytoskeleton morphology in HeLa cells. Moreover, the overexpression of the two variant proteins had inconsistent effects on the target protein PLK4 by western blot analysis, also indicating that T688H variant overexpression is not functionally equivalent to WT-PLK4 overexpression. Therefore, all data support the idea that the PLK4 mutation induces centriolar duplication disorder and reduces the efficiency of mitosis inducing cell death or cell proliferation in the etiology of microcephaly disorder.
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18
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Böhler A, Vermeulen BJA, Würtz M, Zupa E, Pfeffer S, Schiebel E. The gamma-tubulin ring complex: Deciphering the molecular organization and assembly mechanism of a major vertebrate microtubule nucleator. Bioessays 2021; 43:e2100114. [PMID: 34160844 DOI: 10.1002/bies.202100114] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 11/10/2022]
Abstract
Microtubules are protein cylinders with functions in cell motility, signal sensing, cell organization, intracellular transport, and chromosome segregation. One of the key properties of microtubules is their dynamic architecture, allowing them to grow and shrink in length by adding or removing copies of their basic subunit, the heterodimer αβ-tubulin. In higher eukaryotes, de novo assembly of microtubules from αβ-tubulin is initiated by a 2 MDa multi-subunit complex, the gamma-tubulin ring complex (γ-TuRC). For many years, the structure of the γ-TuRC and the function of its subunits remained enigmatic, although structural data from the much simpler yeast counterpart, the γ-tubulin small complex (γ-TuSC), were available. Two recent breakthroughs in the field, high-resolution structural analysis and recombinant reconstitution of the complex, have revolutionized our knowledge about the architecture and function of the γ-TuRC and will form the basis for addressing outstanding questions about biogenesis and regulation of this essential microtubule organizer.
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Affiliation(s)
- Anna Böhler
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Bram J A Vermeulen
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Martin Würtz
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Erik Zupa
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Stefan Pfeffer
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Elmar Schiebel
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
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19
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Kondo H, Matsushita I, Nagata T, Fujihara E, Hosono K, Uchio E, Hotta Y, Kusaka S. Retinal Features of Family Members With Familial Exudative Vitreoretinopathy Caused By Mutations in KIF11 Gene. Transl Vis Sci Technol 2021; 10:18. [PMID: 34128965 PMCID: PMC8212440 DOI: 10.1167/tvst.10.7.18] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/10/2021] [Indexed: 12/02/2022] Open
Abstract
Purpose To determine the clinical characteristics of patients and family members with familial exudative vitreoretinopathy (FEVR) caused by mutations in the KIF11 gene. Methods Twenty-one patients from 10 FEVR families with mutations in the KIF11 gene were studied. The retinal and systemic features were examined. The genetic analyses performed included Sanger sequencing of the KIF11 gene, whole exome sequencing, as well as array comparative genomic hybridization (CGH) analysis and multiple ligation probe assay (MLPA). Results Sequence analysis revealed seven different KIF11 mutations. Array CGH with MLPA revealed two different exon deletions. All probands had advanced FEVR with retinal detachments (RDs) and microcephaly with or without developmental disabilities. Patients with bilateral RDs were more frequently associated with developmental disabilities (P = 0.023). Multimodal imaging of the family members revealed that six of nine patients without RDs (66%) had varying degrees of chorioretinopathy. The retinal folds in FEVR patients were associated with severe retinal avascularization. However, funduscopic changes in the peripheral retina were unremarkable in family members without RDs. A score representing the peripheral vascular anomalies determined from the fluorescein angiograms was lower than that of control eyes of patients with mutations of the Wnt signaling genes (P = 0.0029). Conclusions The probands with KIF11 mutations were associated with severe ocular and systemic pathologies, whereas affected family members showed highly variable clinical manifestations. Peripheral vascular anomalies can often be unremarkable in eyes without RDs. Translational Relevance These findings highlight more diverse mechanisms that underlie the pathological changes in patients with FEVR.
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Affiliation(s)
- Hiroyuki Kondo
- Department of Ophthalmology, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Itsuka Matsushita
- Department of Ophthalmology, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Tatsuo Nagata
- Department of Ophthalmology, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Etsuko Fujihara
- Division of Ophthalmology, Matsue Red Cross Hospital, Matsue, Japan
| | - Katsuhiro Hosono
- Department of Ophthalmology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Eiichi Uchio
- Department of Ophthalmology, Fukuoka University, Fukuoka, Japan
| | - Yoshihiro Hotta
- Department of Ophthalmology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Shunji Kusaka
- Department of Ophthalmology, Kindai University Faculty of Medicine, Osakasayama, Japan
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20
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Shurygina MF, Simonett JM, Parker MA, Mitchell A, Grigorian F, Lifton J, Nagiel A, Shpak AA, Dadali EL, Mishina IA, Weleber RG, Yang P, Pennesi ME. Genotype Phenotype Correlation and Variability in Microcephaly Associated With Chorioretinopathy or Familial Exudative Vitreoretinopathy. Invest Ophthalmol Vis Sci 2021; 61:2. [PMID: 33137195 PMCID: PMC7645200 DOI: 10.1167/iovs.61.13.2] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Purpose The purpose of this study was to analyze the natural history and phenotypic overlap of patients with microcephaly and a chorioretinopathy or familial exudative vitreoretinopathy (FEVR) ocular phenotype caused by mutations in KIF11, TUBGCP4, or TUBGCP6. Methods Patients diagnosed with congenital microcephaly and chorioretinopathy or FEVR were included. Molecular investigations consisted of targeted genetic sequencing. Data from medical records, ophthalmologic examination and imaging, electroretinography, and visual fields were analyzed for systemic and ophthalmic features and evidence of posterior segment disease progression. Results Twelve patients from 9 families were included and had a median of 8 years of follow-up. Nine patients had KIF11 variants, two had heterozygous TUBGCP6 variants, and one had heterozygous variants in TUBGCP4. All patients had reduced visual function and multiple individuals and families showed features of both chorioretinopathy and FEVR. Progression of posterior segment disease was highly variable, with some degree of increased atrophy of the macula or peripheral retina or increased vitreoretinal traction observed in 9 of 12 patients. Conclusions Microcephaly due to mutations in KIF11, TUBGCP4, or TUBGCP6 can be associated with retinal disease on a spectrum from chorioretinal atrophy to FEVR-like posterior segment changes. Visually significant disease progression can occur and patients should be monitored closely by a team experienced in ophthalmic genetics.
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Affiliation(s)
- Maria F Shurygina
- S. Fyodorov Eye Microsurgery Federal State Institution, Moscow, Russia
| | - Joseph M Simonett
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Maria A Parker
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Amanda Mitchell
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Florin Grigorian
- University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States
| | - Jacob Lifton
- Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States
| | - Aaron Nagiel
- Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States.,The Vision Center, Department of Surgery, Children's Hospital Los Angeles, Los Angeles, California, United States.,The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, California, United States
| | - Alexander A Shpak
- S. Fyodorov Eye Microsurgery Federal State Institution, Moscow, Russia
| | - Elena L Dadali
- The Vision Center, Department of Surgery, Children's Hospital Los Angeles, Los Angeles, California, United States
| | - Irina A Mishina
- The Vision Center, Department of Surgery, Children's Hospital Los Angeles, Los Angeles, California, United States
| | - Richard G Weleber
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Paul Yang
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Mark E Pennesi
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
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21
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Sánchez-Bellver L, Toulis V, Marfany G. On the Wrong Track: Alterations of Ciliary Transport in Inherited Retinal Dystrophies. Front Cell Dev Biol 2021; 9:623734. [PMID: 33748110 PMCID: PMC7973215 DOI: 10.3389/fcell.2021.623734] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/09/2021] [Indexed: 01/14/2023] Open
Abstract
Ciliopathies are a group of heterogeneous inherited disorders associated with dysfunction of the cilium, a ubiquitous microtubule-based organelle involved in a broad range of cellular functions. Most ciliopathies are syndromic, since several organs whose cells produce a cilium, such as the retina, cochlea or kidney, are affected by mutations in ciliary-related genes. In the retina, photoreceptor cells present a highly specialized neurosensory cilium, the outer segment, stacked with membranous disks where photoreception and phototransduction occurs. The daily renewal of the more distal disks is a unique characteristic of photoreceptor outer segments, resulting in an elevated protein demand. All components necessary for outer segment formation, maintenance and function have to be transported from the photoreceptor inner segment, where synthesis occurs, to the cilium. Therefore, efficient transport of selected proteins is critical for photoreceptor ciliogenesis and function, and any alteration in either cargo delivery to the cilium or intraciliary trafficking compromises photoreceptor survival and leads to retinal degeneration. To date, mutations in more than 100 ciliary genes have been associated with retinal dystrophies, accounting for almost 25% of these inherited rare diseases. Interestingly, not all mutations in ciliary genes that cause retinal degeneration are also involved in pleiotropic pathologies in other ciliated organs. Depending on the mutation, the same gene can cause syndromic or non-syndromic retinopathies, thus emphasizing the highly refined specialization of the photoreceptor neurosensory cilia, and raising the possibility of photoreceptor-specific molecular mechanisms underlying common ciliary functions such as ciliary transport. In this review, we will focus on ciliary transport in photoreceptor cells and discuss the molecular complexity underpinning retinal ciliopathies, with a special emphasis on ciliary genes that, when mutated, cause either syndromic or non-syndromic retinal ciliopathies.
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Affiliation(s)
- Laura Sánchez-Bellver
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- Institute of Biomedicine (IBUB-IRSJD), Universitat de Barcelona, Barcelona, Spain
| | - Vasileios Toulis
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- CIBERER, ISCIII, Universitat de Barcelona, Barcelona, Spain
| | - Gemma Marfany
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- Institute of Biomedicine (IBUB-IRSJD), Universitat de Barcelona, Barcelona, Spain
- CIBERER, ISCIII, Universitat de Barcelona, Barcelona, Spain
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22
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Gungor S, Oktay Y, Hiz S, Aranguren-Ibáñez Á, Kalafatcilar I, Yaramis A, Karaca E, Yis U, Sonmezler E, Ekinci B, Aslan M, Yilmaz E, Özgör B, Balaraju S, Szabo N, Laurie S, Beltran S, MacArthur DG, Hathazi D, Töpf A, Roos A, Lochmuller H, Vernos I, Horvath R. Autosomal recessive variants in TUBGCP2 alter the γ-tubulin ring complex leading to neurodevelopmental disease. iScience 2021; 24:101948. [PMID: 33458610 PMCID: PMC7797523 DOI: 10.1016/j.isci.2020.101948] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 09/20/2020] [Accepted: 12/11/2020] [Indexed: 12/23/2022] Open
Abstract
Microtubules help building the cytoskeleton of neurons and other cells. Several components of the gamma-tubulin (γ-tubulin) complex have been previously reported in human neurodevelopmental diseases. We describe two siblings from a consanguineous Turkish family with dysmorphic features, developmental delay, brain malformation, and epilepsy carrying a homozygous mutation (p.Glu311Lys) in TUBGCP2 encoding the γ-tubulin complex 2 (GCP2) protein. This variant is predicted to disrupt the electrostatic interaction of GCP2 with GCP3. In primary fibroblasts carrying the variant, we observed a faint delocalization of γ-tubulin during the cell cycle but normal GCP2 protein levels. Through mass spectrometry, we observed dysregulation of multiple proteins involved in the assembly and organization of the cytoskeleton and the extracellular matrix, controlling cellular adhesion and of proteins crucial for neuronal homeostasis including axon guidance. In summary, our functional and proteomic studies link TUBGCP2 and the γ-tubulin complex to the development of the central nervous system in humans.
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Affiliation(s)
- Serdal Gungor
- Inonu University, Faculty of Medicine, Turgut Ozal Research Center, Department of Paediatric Neurology, Malatya, Turkey
| | - Yavuz Oktay
- Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Izmir, Turkey
- Department of Medical Biology, Faculty of Medicine, Dokuz Eylul University and Izmir International Biomedicine and Genome Institute, Dokuz Eylul University, Izmir, Turkey
| | - Semra Hiz
- Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Izmir, Turkey
- Dokuz Eylul University, Faculty of Medicine, Department of Pediatric Neurology Izmir, Turkey
| | - Álvaro Aranguren-Ibáñez
- Centre for Genomic Regulation (CRG), the Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Ipek Kalafatcilar
- Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Izmir, Turkey
- Dokuz Eylul University, Faculty of Medicine, Department of Pediatric Neurology Izmir, Turkey
| | - Ahmet Yaramis
- Pediatric Neurology Clinic, Private Office, Diyarbakir, Turkey
| | - Ezgi Karaca
- Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Izmir, Turkey
- Department of Medical Biology, Faculty of Medicine, Dokuz Eylul University and Izmir International Biomedicine and Genome Institute, Dokuz Eylul University, Izmir, Turkey
| | - Uluc Yis
- Dokuz Eylul University, Faculty of Medicine, Department of Pediatric Neurology Izmir, Turkey
| | - Ece Sonmezler
- Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Izmir, Turkey
| | - Burcu Ekinci
- Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Izmir, Turkey
| | - Mahmut Aslan
- Dokuz Eylul University, Faculty of Medicine, Department of Pediatric Neurology Izmir, Turkey
| | - Elmasnur Yilmaz
- Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Izmir, Turkey
| | - Bilge Özgör
- Inonu University, Faculty of Medicine, Turgut Ozal Research Center, Department of Paediatric Neurology, Malatya, Turkey
| | - Sunitha Balaraju
- John Walton Muscular Dystrophy Research Centre, Institute of Translational and Clinical Research, Newcastle University, Newcastle upon Tyne, UK
- Department of Clinical Neurosciences, John Van Geest Cambridge Centre for Brain Repair, University of Cambridge School of Clinical Medicine, Robinson Way, Cambridge CB2 0PY, UK
| | - Nora Szabo
- Department of Clinical Neurosciences, John Van Geest Cambridge Centre for Brain Repair, University of Cambridge School of Clinical Medicine, Robinson Way, Cambridge CB2 0PY, UK
- Budai Children Hospital, Észak-Közép-budai Centrum, Új Szent János Kórház és Szakrendelő, Budapest, Hungary
| | - Steven Laurie
- CNAG-CRG, Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Sergi Beltran
- CNAG-CRG, Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Daniel G. MacArthur
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Denisa Hathazi
- Department of Clinical Neurosciences, John Van Geest Cambridge Centre for Brain Repair, University of Cambridge School of Clinical Medicine, Robinson Way, Cambridge CB2 0PY, UK
| | - Ana Töpf
- John Walton Muscular Dystrophy Research Centre, Institute of Translational and Clinical Research, Newcastle University, Newcastle upon Tyne, UK
| | - Andreas Roos
- Leibniz Institut für Analytische Wissenschaften, ISAS, Dortmund, Germany & Pediatric Neurology, University Hospital, University of Duisburg-Essen, Faculty of Medicine, Essen, Germany
| | - Hanns Lochmuller
- Children's Hospital of Eastern Ontario Research Institute; Division of Neurology, Department of Medicine, the Ottawa Hospital; and Brain and Mind Research Institute, University of Ottawa, Ottawa, Canada
| | - Isabelle Vernos
- Centre for Genomic Regulation (CRG), the Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Spain
| | - Rita Horvath
- John Walton Muscular Dystrophy Research Centre, Institute of Translational and Clinical Research, Newcastle University, Newcastle upon Tyne, UK
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23
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Yang XR, Benson MD, MacDonald IM, Innes AM. A diagnostic approach to syndromic retinal dystrophies with intellectual disability. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:538-570. [PMID: 32918368 DOI: 10.1002/ajmg.c.31834] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/30/2020] [Accepted: 08/05/2020] [Indexed: 12/20/2022]
Abstract
Inherited retinal dystrophies are a group of monogenic disorders that, as a whole, contribute significantly to the burden of ocular disease in both pediatric and adult patients. In their syndromic forms, retinal dystrophies can be observed in association with intellectual disability, frequently alongside other systemic manifestations. There are now over 80 genes implicated in syndromic retinal dystrophies with intellectual disability. Identifying and accurately characterizing these disorders allows the clinician to narrow the differential diagnosis, evaluate for relevant associated features, arrive at a timely and accurate diagnosis, and address both sight-threatening ocular manifestations and morbidity-causing systemic manifestations. The co-occurrence of retinal dystrophy and intellectual disability in an individual can be challenging to investigate, diagnose, and counsel given the considerable phenotypic and genotypic heterogeneity that exists within this broad group of disorders. We performed a review of the current literature and propose an algorithm to facilitate the evaluation, and clinical and mechanistic classification, of these individuals.
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Affiliation(s)
- Xiao-Ru Yang
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Matthew D Benson
- Department of Ophthalmology, University of Alberta, Edmonton, Alberta, Canada
| | - Ian M MacDonald
- Department of Ophthalmology, University of Alberta, Edmonton, Alberta, Canada.,Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - A Micheil Innes
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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24
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Covello G, Rossello FJ, Filosi M, Gajardo F, Duchemin A, Tremonti BF, Eichenlaub M, Polo JM, Powell D, Ngai J, Allende ML, Domenici E, Ramialison M, Poggi L. Transcriptome analysis of the zebrafish atoh7-/- Mutant, lakritz, highlights Atoh7-dependent genetic networks with potential implications for human eye diseases. FASEB Bioadv 2020; 2:434-448. [PMID: 32676583 PMCID: PMC7354691 DOI: 10.1096/fba.2020-00030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 04/02/2020] [Accepted: 04/28/2020] [Indexed: 12/21/2022] Open
Abstract
Expression of the bHLH transcription protein Atoh7 is a crucial factor conferring competence to retinal progenitor cells for the development of retinal ganglion cells. Several studies have emerged establishing ATOH7 as a retinal disease gene. Remarkably, such studies uncovered ATOH7 variants associated with global eye defects including optic nerve hypoplasia, microphthalmia, retinal vascular disorders, and glaucoma. The complex genetic networks and cellular decisions arising downstream of atoh7 expression, and how their dysregulation cause development of such disease traits remains unknown. To begin to understand such Atoh7-dependent events in vivo, we performed transcriptome analysis of wild-type and atoh7 mutant (lakritz) zebrafish embryos at the onset of retinal ganglion cell differentiation. We investigated in silico interplays of atoh7 and other disease-related genes and pathways. By network reconstruction analysis of differentially expressed genes, we identified gene clusters enriched in retinal development, cell cycle, chromatin remodeling, stress response, and Wnt pathways. By weighted gene coexpression network, we identified coexpression modules affected by the mutation and enriched in retina development genes tightly connected to atoh7. We established the groundwork whereby Atoh7-linked cellular and molecular processes can be investigated in the dynamic multi-tissue environment of the developing normal and diseased vertebrate eye.
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Affiliation(s)
- Giuseppina Covello
- Department of Cellular, Computational and Integrative Biology ‐ CIBIOUniversity of TrentoTrentoItaly
- Present address:
Department of BiologyUniversity of PadovaPadovaItaly
| | - Fernando J. Rossello
- Australian Regenerative Medicine InstituteMonash University Clayton VICClaytonAustralia
- Present address:
University of Melbourne Centre for Cancer ResearchUniversity of MelbourneMelbourneVictoriaAustralia
| | - Michele Filosi
- Department of Cellular, Computational and Integrative Biology ‐ CIBIOUniversity of TrentoTrentoItaly
| | - Felipe Gajardo
- Center for Genome RegulationFacultad de Ciencias, SantiagoUniversidad de ChileSantiagoChile
| | | | - Beatrice F. Tremonti
- Department of Cellular, Computational and Integrative Biology ‐ CIBIOUniversity of TrentoTrentoItaly
| | - Michael Eichenlaub
- Australian Regenerative Medicine InstituteMonash University Clayton VICClaytonAustralia
| | - Jose M. Polo
- Australian Regenerative Medicine InstituteMonash University Clayton VICClaytonAustralia
- BDIMonash University Clayton VICClaytonAustralia
| | - David Powell
- Monash Bioinformatics PlatformMonash University Clayton VICClaytonAustralia
| | - John Ngai
- Department of Molecular and Cell Biology & Helen Wills Neuroscience InstituteUniversity of CaliforniaBerkeleyCAUSA
| | - Miguel L. Allende
- Center for Genome RegulationFacultad de Ciencias, SantiagoUniversidad de ChileSantiagoChile
| | - Enrico Domenici
- Department of Cellular, Computational and Integrative Biology ‐ CIBIOUniversity of TrentoTrentoItaly
- Fondazione The Microsoft Research ‐ University of Trento Centre for Computational and Systems BiologyTrentoItaly
| | - Mirana Ramialison
- Australian Regenerative Medicine InstituteMonash University Clayton VICClaytonAustralia
| | - Lucia Poggi
- Department of Cellular, Computational and Integrative Biology ‐ CIBIOUniversity of TrentoTrentoItaly
- Centre for Organismal StudyHeidelberg UniversityHeidelbergGermany
- Department of PhysiologyDevelopment and NeuroscienceUniversity of CambridgeCambridgeUnited Kingdom
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25
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Kröll-Hermi A, Ebstein F, Stoetzel C, Geoffroy V, Schaefer E, Scheidecker S, Bär S, Takamiya M, Kawakami K, Zieba BA, Studer F, Pelletier V, Eyermann C, Speeg-Schatz C, Laugel V, Lipsker D, Sandron F, McGinn S, Boland A, Deleuze JF, Kuhn L, Chicher J, Hammann P, Friant S, Etard C, Krüger E, Muller J, Strähle U, Dollfus H. Proteasome subunit PSMC3 variants cause neurosensory syndrome combining deafness and cataract due to proteotoxic stress. EMBO Mol Med 2020; 12:e11861. [PMID: 32500975 PMCID: PMC7338805 DOI: 10.15252/emmm.201911861] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 05/04/2020] [Accepted: 05/07/2020] [Indexed: 12/13/2022] Open
Abstract
The ubiquitin–proteasome system degrades ubiquitin‐modified proteins to maintain protein homeostasis and to control signalling. Whole‐genome sequencing of patients with severe deafness and early‐onset cataracts as part of a neurological, sensorial and cutaneous novel syndrome identified a unique deep intronic homozygous variant in the PSMC3 gene, encoding the proteasome ATPase subunit Rpt5, which lead to the transcription of a cryptic exon. The proteasome content and activity in patient's fibroblasts was however unaffected. Nevertheless, patient's cells exhibited impaired protein homeostasis characterized by accumulation of ubiquitinated proteins suggesting severe proteotoxic stress. Indeed, the TCF11/Nrf1 transcriptional pathway allowing proteasome recovery after proteasome inhibition is permanently activated in the patient's fibroblasts. Upon chemical proteasome inhibition, this pathway was however impaired in patient's cells, which were unable to compensate for proteotoxic stress although a higher proteasome content and activity. Zebrafish modelling for knockout in PSMC3 remarkably reproduced the human phenotype with inner ear development anomalies as well as cataracts, suggesting that Rpt5 plays a major role in inner ear, lens and central nervous system development.
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Affiliation(s)
- Ariane Kröll-Hermi
- Laboratoire de Génétique Médicale, INSERM, UMRS_1112, Institut de Génétique Médicale d'Alsace (IGMA), Université de Strasbourg, Faculté de médecine de Strasbourg, Strasbourg, France.,Karlsruhe Institute of Technology (KIT), Institut für Biologische und Chemische Systeme (IBCS, BIP), Eggenstein-Leopoldshafen, Germany
| | - Frédéric Ebstein
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Greifswald, Germany
| | - Corinne Stoetzel
- Laboratoire de Génétique Médicale, INSERM, UMRS_1112, Institut de Génétique Médicale d'Alsace (IGMA), Université de Strasbourg, Faculté de médecine de Strasbourg, Strasbourg, France
| | - Véronique Geoffroy
- Laboratoire de Génétique Médicale, INSERM, UMRS_1112, Institut de Génétique Médicale d'Alsace (IGMA), Université de Strasbourg, Faculté de médecine de Strasbourg, Strasbourg, France
| | - Elise Schaefer
- Laboratoire de Génétique Médicale, INSERM, UMRS_1112, Institut de Génétique Médicale d'Alsace (IGMA), Université de Strasbourg, Faculté de médecine de Strasbourg, Strasbourg, France.,Service de Génétique Médicale, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Sophie Scheidecker
- Laboratoire de Génétique Médicale, INSERM, UMRS_1112, Institut de Génétique Médicale d'Alsace (IGMA), Université de Strasbourg, Faculté de médecine de Strasbourg, Strasbourg, France.,Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Séverine Bär
- Laboratoire de Génétique Moléculaire, Génomique, Microbiologie (GMGM), UMR7156, Centre National de Recherche Scientifique (CNRS), Université de Strasbourg, Strasbourg, France
| | - Masanari Takamiya
- Karlsruhe Institute of Technology (KIT), Institut für Biologische und Chemische Systeme (IBCS, BIP), Eggenstein-Leopoldshafen, Germany
| | - Koichi Kawakami
- Laboratory of Molecular and Developmental Biology, National Institute of Genetics, Mishima, Japan.,Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima, Japan
| | - Barbara A Zieba
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Greifswald, Germany
| | - Fouzia Studer
- Filière SENSGENE, Centre de Référence pour les affections rares en génétique ophtalmologique, CARGO, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Valerie Pelletier
- Service de Génétique Médicale, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.,Filière SENSGENE, Centre de Référence pour les affections rares en génétique ophtalmologique, CARGO, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Carine Eyermann
- Service de chirurgie ORL, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Claude Speeg-Schatz
- Department of Ophthalmology, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Vincent Laugel
- Laboratoire de Génétique Médicale, INSERM, UMRS_1112, Institut de Génétique Médicale d'Alsace (IGMA), Université de Strasbourg, Faculté de médecine de Strasbourg, Strasbourg, France.,Service de Pédiatrie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Dan Lipsker
- Faculté de Médecine, Hôpitaux Universitaires, Université de Strasbourg et Clinique Dermatologique, Strasbourg, France
| | - Florian Sandron
- Centre National de Recherche en Génomique Humaine (CNRGH), Institut de Biologie François Jacob, CEA, Université Paris-Saclay, Evry, France
| | - Steven McGinn
- Centre National de Recherche en Génomique Humaine (CNRGH), Institut de Biologie François Jacob, CEA, Université Paris-Saclay, Evry, France
| | - Anne Boland
- Centre National de Recherche en Génomique Humaine (CNRGH), Institut de Biologie François Jacob, CEA, Université Paris-Saclay, Evry, France
| | - Jean-François Deleuze
- Centre National de Recherche en Génomique Humaine (CNRGH), Institut de Biologie François Jacob, CEA, Université Paris-Saclay, Evry, France.,Centre d'études du polymorphisme humain-Fondation Jean Dausset, Paris, France
| | - Lauriane Kuhn
- CNRS FRC1589, Institut de Biologie Moléculaire et Cellulaire (IBMC), Plateforme Protéomique Strasbourg-Esplanade, Strasbourg, France
| | - Johana Chicher
- CNRS FRC1589, Institut de Biologie Moléculaire et Cellulaire (IBMC), Plateforme Protéomique Strasbourg-Esplanade, Strasbourg, France
| | - Philippe Hammann
- CNRS FRC1589, Institut de Biologie Moléculaire et Cellulaire (IBMC), Plateforme Protéomique Strasbourg-Esplanade, Strasbourg, France
| | - Sylvie Friant
- Laboratoire de Génétique Moléculaire, Génomique, Microbiologie (GMGM), UMR7156, Centre National de Recherche Scientifique (CNRS), Université de Strasbourg, Strasbourg, France
| | - Christelle Etard
- Karlsruhe Institute of Technology (KIT), Institut für Biologische und Chemische Systeme (IBCS, BIP), Eggenstein-Leopoldshafen, Germany
| | - Elke Krüger
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Greifswald, Germany
| | - Jean Muller
- Laboratoire de Génétique Médicale, INSERM, UMRS_1112, Institut de Génétique Médicale d'Alsace (IGMA), Université de Strasbourg, Faculté de médecine de Strasbourg, Strasbourg, France.,Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Uwe Strähle
- Karlsruhe Institute of Technology (KIT), Institut für Biologische und Chemische Systeme (IBCS, BIP), Eggenstein-Leopoldshafen, Germany
| | - Hélène Dollfus
- Laboratoire de Génétique Médicale, INSERM, UMRS_1112, Institut de Génétique Médicale d'Alsace (IGMA), Université de Strasbourg, Faculté de médecine de Strasbourg, Strasbourg, France.,Service de Génétique Médicale, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.,Filière SENSGENE, Centre de Référence pour les affections rares en génétique ophtalmologique, CARGO, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
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26
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Da Palma MM, Motta FL, Takitani GEDS, Salles MV, Lima LH, Ferraz Sallum JM. TUBGCP4 - associated microcephaly and chorioretinopathy. Ophthalmic Genet 2020; 41:189-193. [PMID: 32270730 DOI: 10.1080/13816810.2020.1747084] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Background Microcephaly and chorioretinopathy (MCCRP) is a rare neuro-ophthalmologic disorder that causes microcephaly and chorioretinopathy. In a recessive inheritance pattern, there are three types: MCCRP1; MCCRP2 and MCCRP3. MCCRP3 results from pathogenic variants in the tubulin-gamma complex-associated protein 4 (TUBGCP4) gene.Materials and Methods This is a case report of a patient with a molecular diagnosis defined by mutations in the TUBGCP4 gene. Segregation analyses were carried out.Results The molecular investigation found two heterozygous variants c.1380 G > A (p.Trp460*) a novel nonsense variant, and c.1746 G > T (p Leu582=) a synonymous variant in TUBGCP4. The clinical phenotype was characterized by microcephaly, microphthalmia, chorioretinopathy, a punched-out retinal appearance, dysmorphic facial features, decreased visual acuity, and learning difficulties. The clinical features were similar to those described previously in children with MCCRP3. The proband also had additional features including centripetal obesity, stretch marks, acanthosis nigricans, scoliosis, and hypercholesterolemia. These other features could be part of a ciliopathy syndrome.Conclusions MCCRP2 caused by pathogenic variants in PLK4 is well established as a ciliopathy disease. The role of TUBGCP4 is not well established in the cilium physiology. MCCRP3 may be part of the ciliopathy spectrum.
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Affiliation(s)
| | | | | | | | - Luiz Henrique Lima
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - Juliana Maria Ferraz Sallum
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil.,Department of Ocular Genetics, Instituto De Genética Ocular, São Paulo, Brazil
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27
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Nasser H, Vera L, Elmaleh-Bergès M, Steindl K, Letard P, Teissier N, Ernault A, Guimiot F, Afenjar A, Moutard ML, Héron D, Alembik Y, Momtchilova M, Milani P, Kubis N, Pouvreau N, Zollino M, Guilmin Crepon S, Kaguelidou F, Gressens P, Verloes A, Rauch A, El Ghouzzi V, Drunat S, Passemard S. CDK5RAP2 primary microcephaly is associated with hypothalamic, retinal and cochlear developmental defects. J Med Genet 2020; 57:389-399. [PMID: 32015000 DOI: 10.1136/jmedgenet-2019-106474] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 11/22/2019] [Accepted: 11/29/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Primary hereditary microcephaly (MCPH) comprises a large group of autosomal recessive disorders mainly affecting cortical development and resulting in a congenital impairment of brain growth. Despite the identification of >25 causal genes so far, it remains a challenge to distinguish between different MCPH forms at the clinical level. METHODS 7 patients with newly identified mutations in CDK5RAP2 (MCPH3) were investigated by performing prospective, extensive and systematic clinical, MRI, psychomotor, neurosensory and cognitive examinations under similar conditions. RESULTS All patients displayed neurosensory defects in addition to microcephaly. Small cochlea with incomplete partition type II was found in all cases and was associated with progressive deafness in 4 of them. Furthermore, the CDK5RAP2 protein was specifically identified in the developing cochlea from human fetal tissues. Microphthalmia was also present in all patients along with retinal pigmentation changes and lipofuscin deposits. Finally, hypothalamic anomalies consisting of interhypothalamic adhesions, a congenital midline defect usually associated with holoprosencephaly, was detected in 5 cases. CONCLUSION This is the first report indicating that CDK5RAP2 not only governs brain size but also plays a role in ocular and cochlear development and is necessary for hypothalamic nuclear separation at the midline. Our data indicate that CDK5RAP2 should be considered as a potential gene associated with deafness and forme fruste of holoprosencephaly. These children should be given neurosensory follow-up to prevent additional comorbidities and allow them reaching their full educational potential. TRIAL REGISTRATION NUMBER NCT01565005.
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Affiliation(s)
- Hala Nasser
- Département de Génétique, APHP, Hopital Robert Debré, 75019 Paris, France.,Service des Explorations Fonctionnelles, APHP, Hopital Robert Debré, 75019 Paris, France
| | - Liza Vera
- Service d'Ophtalmologie, APHP, Hopital Robert Debré, 75019 Paris, France
| | | | - Katharina Steindl
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland
| | - Pascaline Letard
- Département de Génétique, APHP, Hopital Robert Debré, 75019 Paris, France.,Université de Paris, NeuroDiderot, Inserm, F-75019 Paris, France.,Service d'Anatomopathologie, Hopital Jean Verdier, APHP, Bondy, France.,Université Paris 13, 93140 Bondy, France
| | - Natacha Teissier
- Université de Paris, NeuroDiderot, Inserm, F-75019 Paris, France.,Service d'ORL, APHP, Hopital Robert Debré, 75019 Paris, France
| | - Anais Ernault
- Département de Génétique, APHP, Hopital Robert Debré, 75019 Paris, France
| | - Fabien Guimiot
- Université de Paris, NeuroDiderot, Inserm, F-75019 Paris, France.,Service de Foetopathologie, APHP, Hopital Robert Debré, 75019 Paris, France
| | - Alexandra Afenjar
- CRMR déficiences intellectuelles de causes rares, Département de génétique, Sorbonne Université, APHP, Hôpital Trousseau, 75012 Paris, France
| | | | - Delphine Héron
- Département de Génétique, APHP, Hopital La Pitié-Salpetriere, 75013 Paris, France
| | - Yves Alembik
- Service de Génétique Médicale, CHU de Strasbourg, Hopital de Hautepierre, 67200 Strasbourg, France
| | | | - Paolo Milani
- Service des Explorations Fonctionnelles, APHP, Hopital Lariboisière, 75010 Paris, France
| | - Nathalie Kubis
- Service des Explorations Fonctionnelles, APHP, Hopital Lariboisière, 75010 Paris, France
| | - Nathalie Pouvreau
- Département de Génétique, APHP, Hopital Robert Debré, 75019 Paris, France
| | - Marcella Zollino
- Universita Cattolica Sacro Cuore Istituto di Medicina Genomica, Roma, Italy.,Fondazione Policlinico A. Gemelli IRCCS, Roma, Italy
| | | | - Florentia Kaguelidou
- Université de Paris, Centre d'Investigation Clinique, CIC 1426, INSERM, APHP, Hopital Robert Debré, 75019 Paris, France
| | - Pierre Gressens
- Université de Paris, NeuroDiderot, Inserm, F-75019 Paris, France.,Center for Developing Brain, King's College, St. Thomas' Campus, London, United Kingdom
| | - Alain Verloes
- Département de Génétique, APHP, Hopital Robert Debré, 75019 Paris, France.,Université de Paris, NeuroDiderot, Inserm, F-75019 Paris, France.,European Reference Network ERN ITHACA, 75019 Paris, France
| | - Anita Rauch
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland
| | | | - Severine Drunat
- Département de Génétique, APHP, Hopital Robert Debré, 75019 Paris, France.,Université de Paris, NeuroDiderot, Inserm, F-75019 Paris, France.,European Reference Network ERN ITHACA, 75019 Paris, France
| | - Sandrine Passemard
- Département de Génétique, APHP, Hopital Robert Debré, 75019 Paris, France .,Université de Paris, NeuroDiderot, Inserm, F-75019 Paris, France.,European Reference Network ERN ITHACA, 75019 Paris, France.,Service de Neuropédiatrie, APHP, Hopital Robert Debré, 75019 Paris, France
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Haren L, Farache D, Emorine L, Merdes A. A stable core of GCPs 4, 5 and 6 promotes the assembly of γ-tubulin ring complexes. J Cell Sci 2020; 133:jcs.244368. [DOI: 10.1242/jcs.244368] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 03/26/2020] [Indexed: 12/28/2022] Open
Abstract
γ-tubulin is a major protein involved in the nucleation of microtubules in all eukaryotes. It forms two different complexes with proteins of the GCP family (gamma-tubulin complex proteins): γ-tubulin small complexes (γTuSCs), containing γ-tubulin and GCPs 2 and 3, and γ-tubulin ring complexes (γTuRCs), containing multiple γTuSCs, in addition to GCPs 4, 5, and 6. Whereas the structure and assembly properties of γTuSCs have been intensively studied, little is known about the assembly of γTuRCs, and about the specific roles of GCPs 4, 5, and 6. Here, we demonstrate that two copies of GCP4 and one copy each of GCP5 and GCP6 form a salt-resistant sub-complex within the γTuRC that assembles independently of the presence of γTuSCs. Incubation of this sub-complex with cytoplasmic extracts containing γTuSCs leads to the reconstitution of γTuRCs that are competent to nucleate microtubules. In addition, we investigate sequence extensions and insertions that are specifically found at the amino-terminus of GCP6, and between the GCP6 grip1 and grip2 motifs, and we demonstrate that these are involved in the assembly or stabilization of the γTuRC.
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Affiliation(s)
- Laurence Haren
- Centre de Biologie du Développement, Centre de Biologie Intégrative, CNRS-Université Toulouse III, 31062 Toulouse, France
| | - Dorian Farache
- Centre de Biologie du Développement, Centre de Biologie Intégrative, CNRS-Université Toulouse III, 31062 Toulouse, France
| | - Laurent Emorine
- Centre de Biologie du Développement, Centre de Biologie Intégrative, CNRS-Université Toulouse III, 31062 Toulouse, France
| | - Andreas Merdes
- Centre de Biologie du Développement, Centre de Biologie Intégrative, CNRS-Université Toulouse III, 31062 Toulouse, France
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Rare missense TUBGCP5 gene variant in a patient with primary microcephaly. Eur J Med Genet 2019; 62:103598. [DOI: 10.1016/j.ejmg.2018.12.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 12/06/2018] [Accepted: 12/08/2018] [Indexed: 12/20/2022]
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Mitani T, Punetha J, Akalin I, Pehlivan D, Dawidziuk M, Coban Akdemir Z, Yilmaz S, Aslan E, Hunter JV, Hijazi H, Grochowski CM, Jhangiani SN, Karaca E, Fatih JM, Iwanowski P, Gambin T, Wlasienko P, Goszczanska-Ciuchta A, Bekiesinska-Figatowska M, Hosseini M, Arzhangi S, Najmabadi H, Rosenfeld JA, Du H, Marafi D, Blaser S, Teitelbaum R, Silver R, Posey JE, Ropers HH, Gibbs RA, Wiszniewski W, Lupski JR, Chitayat D, Kahrizi K, Gawlinski P, Gawlinski P. Bi-allelic Pathogenic Variants in TUBGCP2 Cause Microcephaly and Lissencephaly Spectrum Disorders. Am J Hum Genet 2019; 105:1005-1015. [PMID: 31630790 DOI: 10.1016/j.ajhg.2019.09.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 09/13/2019] [Indexed: 10/25/2022] Open
Abstract
Lissencephaly comprises a spectrum of malformations of cortical development. This spectrum includes agyria, pachygyria, and subcortical band heterotopia; each represents anatomical malformations of brain cortical development caused by neuronal migration defects. The molecular etiologies of neuronal migration anomalies are highly enriched for genes encoding microtubules and microtubule-associated proteins, and this enrichment highlights the critical role for these genes in cortical growth and gyrification. Using exome sequencing and family based rare variant analyses, we identified a homozygous variant (c.997C>T [p.Arg333Cys]) in TUBGCP2, encoding gamma-tubulin complex protein 2 (GCP2), in two individuals from a consanguineous family; both individuals presented with microcephaly and developmental delay. GCP2 forms the multiprotein γ-tubulin ring complex (γ-TuRC) together with γ-tubulin and other GCPs to regulate the assembly of microtubules. By querying clinical exome sequencing cases and through GeneMatcher-facilitated collaborations, we found three additional families with bi-allelic variation and similarly affected phenotypes including a homozygous variant (c.1843G>C [p.Ala615Pro]) in two families and compound heterozygous variants consisting of one missense variant (c.889C>T [p.Arg297Cys]) and one splice variant (c.2025-2A>G) in another family. Brain imaging from all five affected individuals revealed varying degrees of cortical malformations including pachygyria and subcortical band heterotopia, presumably caused by disruption of neuronal migration. Our data demonstrate that pathogenic variants in TUBGCP2 cause an autosomal recessive neurodevelopmental trait consisting of a neuronal migration disorder, and our data implicate GCP2 as a core component of γ-TuRC in neuronal migrating cells.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Pawel Gawlinski
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, 01-211, Poland.
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31
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Hull S, Arno G, Ostergaard P, Pontikos N, Robson AG, Webster AR, Hogg CR, Wright GA, Henderson RHH, Martin CA, Jackson AP, Mansour S, Moore AT, Michaelides M. Clinical and Molecular Characterization of Familial Exudative Vitreoretinopathy Associated With Microcephaly. Am J Ophthalmol 2019; 207:87-98. [PMID: 31077665 DOI: 10.1016/j.ajo.2019.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 04/29/2019] [Accepted: 05/01/2019] [Indexed: 12/11/2022]
Abstract
PURPOSE Familial exudative vitreoretinopathy (FEVR) is a rare finding in patients with genetic forms of microcephaly. This study documents the detailed phenotype and expands the range of genetic heterogeneity. DESIGN Retrospective case series. METHODS Twelve patients (10 families) with a diagnosis of FEVR and microcephaly were ascertained from pediatric genetic eye clinics and underwent full clinical assessment including retinal imaging. Molecular investigations included candidate gene Sanger sequencing, whole-exome sequencing (WES), and whole-genome sequencing (WGS). RESULTS All patients had reduced vision and nystagmus. Six were legally blind. Two probands carried bi-allelic LRP5 variants, both presenting with bilateral retinal folds. A novel homozygous splice variant, and 2 missense variants were identified. Subsequent bone density measurement identified osteoporosis in one proband. Four families had heterozygous KIF11 variants. Two probands had a retinal fold in one eye and chorioretinal atrophy in the other; the other 2 had bilateral retinal folds. Four heterozygous variants were found, including 2 large deletions not identified on Sanger sequencing or WES. Finally, a family of 2 children with learning difficulties, abnormal peripheral retinal vasculogenesis, and rod-cone dystrophy were investigated. They were found to have bi-allelic splicing variants in TUBGCP6. Three families remain unsolved following WES and WGS. CONCLUSIONS Molecular diagnosis has been achieved in 7 of 10 families investigated, including a previously unrecognized association with LRP5. WGS enabled molecular diagnosis in 3 families after prior negative Sanger sequencing of the causative gene. This has enabled patient-specific care with targeted investigations and accurate family counseling.
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Affiliation(s)
- Sarah Hull
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Gavin Arno
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Pia Ostergaard
- Genetics Research Centre, Molecular and Clinical Sciences, St George's University of London, London, United Kingdom
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Anthony G Robson
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Andrew R Webster
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Chris R Hogg
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Genevieve A Wright
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Robert H H Henderson
- Moorfields Eye Hospital, London, United Kingdom; Ophthalmology Department, Great Ormond Street Hospital for Children, London, United Kingdom
| | - Carol-Anne Martin
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Andrew P Jackson
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Sahar Mansour
- Genetics Research Centre, Molecular and Clinical Sciences, St George's University of London, London, United Kingdom; South West Thames Regional Genetics Service, St George's Healthcare NHS Trust, London, United Kingdom
| | - Anthony T Moore
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom; Ophthalmology Department, University of California, San Francisco, California
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom.
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32
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Xu X, Shang D, Cheng H, Klionsky DJ, Zhou R. Gene essentiality of Tubgcp4: dosage effect and autophagy regulation in retinal photoreceptors. Autophagy 2019; 15:1834-1837. [PMID: 31345090 DOI: 10.1080/15548627.2019.1647023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Photoreceptor degeneration and damages often lead to blindness, and the underlying molecular mechanisms are largely unknown. There is also a lot of missing information for establishing the role of macroautophagy/autophagy in the retinopathy. We recently generated knockout mouse lines of the essential gene Tubgcp4 (tubulin, gamma complex associated protein 4) and revealed an interplay between essential genes and autophagy regulation. Complete knockout of Tubgcp4 in mice results in early embryonic lethality due to abnormal spindle assembly, whereas heterozygotes are viable through dosage compensation from one wild-type allele, suggesting a dosage effect of the essential gene. However, haploinsufficiency of TUBGCP4 impairs assembly of TUBG/γ-tubulin ring complexes and disturbs autophagy homeostasis of the retina, with pathological phenotypes of photoreceptor degeneration and a decrease of electroretinography responses. TUBGCP4 can inhibit autophagy by competing with ATG3 to interact with ATG7, thus interfering with lipidation of LC3B. Taken together, these findings demonstrate dosage effect of the essential gene Tubgcp4 for viability of mutant mice, and suggest key roles of TUBGCP4 in embryo development and retinal homeostasis by autophagy regulation. Abbreviations: ATG3: autophagy related 3; ATG7: autophagy related 7; CRISPR: clustered regularly interspaced short palindromic repeats; ERG: electroretinography; HCQ: hydroxychloroquine; LC3B: microtubule-associated protein 1 light chain 3 beta; NFE2L2: nuclear factor, erythroid 2 like 2; ONL: outer nuclear layer; PPARGC1A: peroxisome proliferator-activated receptor gamma coactivator-1 alpha; RB1CC1: RB1 inducible coiled-coil 1; SQSTM1: sequestosome 1; TUBGCP: tubulin, gamma complex associated protein; TUBGRC/γ: TuRCs gamma-tubulin ring complexes.
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Affiliation(s)
- Xu Xu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University , Wuhan , China
| | - Dantong Shang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University , Wuhan , China
| | - Hanhua Cheng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University , Wuhan , China
| | - Daniel J Klionsky
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan , Ann Arbor , MI , USA
| | - Rongjia Zhou
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University , Wuhan , China
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Haploinsufficiency of GCP4 induces autophagy and leads to photoreceptor degeneration due to defective spindle assembly in retina. Cell Death Differ 2019; 27:556-572. [PMID: 31209365 PMCID: PMC7206048 DOI: 10.1038/s41418-019-0371-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 06/03/2019] [Accepted: 06/04/2019] [Indexed: 01/01/2023] Open
Abstract
Retinopathy, owing to damage to the retina, often causes vision impairment, and the underlying molecular mechanisms are largely unknown. Using a gene targeting strategy, we generated mice with the essential gene Tubgcp4 knocked out. Homozygous mutation of Tubgcp4 resulted in early embryonic lethality due to abnormal spindle assembly caused by GCP4 (gamma-tubulin complex protein 4, encoded by Tubgcp4) depletion. Heterozygotes were viable through dosage compensation of one wild-type allele. However, haploinsufficiency of GCP4 affected the assembly of γ-TuRCs (γ-tubulin ring complexes) and disrupted autophagy homeostasis in retina, thus leading to photoreceptor degeneration and retinopathy. Notably, GCP4 exerted autophagy inhibition by competing with ATG3 for interaction with ATG7, thus interfering with lipidation of LC3B. Our findings justify dosage effects of essential genes that compensate for null alleles in viability of mutant mice and uncover dosage-dependent roles of GCP4 in embryo development and retinal homeostasis. These data have also clinical implications in genetic counseling on embryonic lethality and in development of potential therapeutic targets associated with retinopathy.
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Abstract
Microtubules are major constituents of the cytoskeleton in all eukaryotic cells. They are essential for chromosome segregation during cell division, for directional intracellular transport and for building specialized cellular structures such as cilia or flagella. Their assembly has to be controlled spatially and temporally. For this, the cell uses multiprotein complexes containing γ-tubulin. γ-Tubulin has been found in two different types of complexes, γ-tubulin small complexes and γ-tubulin ring complexes. Binding to adaptors and activator proteins transforms these complexes into structural templates that drive the nucleation of new microtubules in a highly controlled manner. This review discusses recent advances on the mechanisms of assembly, recruitment and activation of γ-tubulin complexes at microtubule-organizing centres.
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Affiliation(s)
- Dorian Farache
- Centre de Biologie Intégrative, Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France
| | - Laurent Emorine
- Centre de Biologie Intégrative, Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France
| | - Laurence Haren
- Centre de Biologie Intégrative, Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France
| | - Andreas Merdes
- Centre de Biologie Intégrative, Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France
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35
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Papageorgiou E, Pilat A, Proudlock F, Lee H, Purohit R, Sheth V, Vasudevan P, Gottlob I. Retinal and optic nerve changes in microcephaly: An optical coherence tomography study. Neurology 2018; 91:e571-e585. [PMID: 29997194 PMCID: PMC6105049 DOI: 10.1212/wnl.0000000000005950] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 04/27/2018] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVE To investigate the morphology of the retina and optic nerve (ON) in microcephaly. METHODS This was a prospective case-control study including 27 patients with microcephaly and 27 healthy controls. All participants underwent ophthalmologic examination and handheld optical coherence tomography (OCT) of the macula and ON head. The thickness of individual retinal layers was quantified at the foveal center and the parafovea (1,000 μm nasal and temporal to the fovea). For the ON head, disc diameter, cup diameter, cup-to-disc ratio, cup depth, horizontal rim diameter, rim area, peripapillary retinal thickness, and retinal nerve fiber layer thickness were measured. RESULTS Seventy-eight percent of patients had ophthalmologic abnormalities, mainly nystagmus (56%) and strabismus (52%). OCT abnormalities were found in 85% of patients. OCT revealed disruption of the ellipsoid zone, persistent inner retinal layers, and irregular foveal pits. Parafoveal retinal thickness was significantly reduced in patients with microcephaly compared to controls, nasally (307 ± 44 vs 342 ± 19 μm, p = 0.001) and temporally (279 ± 56 vs 325 ± 16 μm, p < 0.001). There was thinning of the ganglion cell layer and the inner segments of the photoreceptors in microcephaly. Total peripapillary retinal thickness was smaller in patients with microcephaly compared to controls for both temporal (275 vs 318 μm, p < 0.001) and nasal sides (239 vs 268 μm, p = 0.013). CONCLUSIONS Retinal and ON anomalies in microcephaly likely reflect retinal cell reduction and lamination alteration due to impaired neurogenic mitosis. OCT allows diagnosis and quantification of retinal and ON changes in microcephaly even if they are not detected on ophthalmoscopy.
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Affiliation(s)
- Eleni Papageorgiou
- From the Department of Ophthalmology (E.P., A.P., F.P., H.L., R.P., V.S., I.G.), Leicester Royal Infirmary, University of Leicester; and Department of Clinical Genetics (P.V.), University Hospitals of Leicester, Leicester Royal Infirmary, UK
| | - Anastasia Pilat
- From the Department of Ophthalmology (E.P., A.P., F.P., H.L., R.P., V.S., I.G.), Leicester Royal Infirmary, University of Leicester; and Department of Clinical Genetics (P.V.), University Hospitals of Leicester, Leicester Royal Infirmary, UK
| | - Frank Proudlock
- From the Department of Ophthalmology (E.P., A.P., F.P., H.L., R.P., V.S., I.G.), Leicester Royal Infirmary, University of Leicester; and Department of Clinical Genetics (P.V.), University Hospitals of Leicester, Leicester Royal Infirmary, UK
| | - Helena Lee
- From the Department of Ophthalmology (E.P., A.P., F.P., H.L., R.P., V.S., I.G.), Leicester Royal Infirmary, University of Leicester; and Department of Clinical Genetics (P.V.), University Hospitals of Leicester, Leicester Royal Infirmary, UK
| | - Ravi Purohit
- From the Department of Ophthalmology (E.P., A.P., F.P., H.L., R.P., V.S., I.G.), Leicester Royal Infirmary, University of Leicester; and Department of Clinical Genetics (P.V.), University Hospitals of Leicester, Leicester Royal Infirmary, UK
| | - Viral Sheth
- From the Department of Ophthalmology (E.P., A.P., F.P., H.L., R.P., V.S., I.G.), Leicester Royal Infirmary, University of Leicester; and Department of Clinical Genetics (P.V.), University Hospitals of Leicester, Leicester Royal Infirmary, UK
| | - Pradeep Vasudevan
- From the Department of Ophthalmology (E.P., A.P., F.P., H.L., R.P., V.S., I.G.), Leicester Royal Infirmary, University of Leicester; and Department of Clinical Genetics (P.V.), University Hospitals of Leicester, Leicester Royal Infirmary, UK
| | - Irene Gottlob
- From the Department of Ophthalmology (E.P., A.P., F.P., H.L., R.P., V.S., I.G.), Leicester Royal Infirmary, University of Leicester; and Department of Clinical Genetics (P.V.), University Hospitals of Leicester, Leicester Royal Infirmary, UK.
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36
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Goffinet AM. The evolution of cortical development: the synapsid-diapsid divergence. Development 2017; 144:4061-4077. [PMID: 29138289 DOI: 10.1242/dev.153908] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The cerebral cortex covers the rostral part of the brain and, in higher mammals and particularly humans, plays a key role in cognition and consciousness. It is populated with neuronal cell bodies distributed in radially organized layers. Understanding the common and lineage-specific molecular mechanisms that orchestrate cortical development and evolution are key issues in neurobiology. During evolution, the cortex appeared in stem amniotes and evolved divergently in two main branches of the phylogenetic tree: the synapsids (which led to present day mammals) and the diapsids (reptiles and birds). Comparative studies in organisms that belong to those two branches have identified some common principles of cortical development and organization that are possibly inherited from stem amniotes and regulated by similar molecular mechanisms. These comparisons have also highlighted certain essential features of mammalian cortices that are absent or different in diapsids and that probably evolved after the synapsid-diapsid divergence. Chief among these is the size and multi-laminar organization of the mammalian cortex, and the propensity to increase its area by folding. Here, I review recent data on cortical neurogenesis, neuronal migration and cortical layer formation and folding in this evolutionary perspective, and highlight important unanswered questions for future investigation.
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Affiliation(s)
- Andre M Goffinet
- University of Louvain, Avenue Mounier, 73 Box B1.73.16, B1200 Brussels, Belgium
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37
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Genetic characterization and disease mechanism of retinitis pigmentosa; current scenario. 3 Biotech 2017; 7:251. [PMID: 28721681 DOI: 10.1007/s13205-017-0878-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 07/10/2017] [Indexed: 12/21/2022] Open
Abstract
Retinitis pigmentosa is a group of genetically transmitted disorders affecting 1 in 3000-8000 individual people worldwide ultimately affecting the quality of life. Retinitis pigmentosa is characterized as a heterogeneous genetic disorder which leads by progressive devolution of the retina leading to a progressive visual loss. It can occur in syndromic (with Usher syndrome and Bardet-Biedl syndrome) as well as non-syndromic nature. The mode of inheritance can be X-linked, autosomal dominant or autosomal recessive manner. To date 58 genes have been reported to associate with retinitis pigmentosa most of them are either expressed in photoreceptors or the retinal pigment epithelium. This review focuses on the disease mechanisms and genetics of retinitis pigmentosa. As retinitis pigmentosa is tremendously heterogeneous disorder expressing a multiplicity of mutations; different variations in the same gene might induce different disorders. In recent years, latest technologies including whole-exome sequencing contributing effectively to uncover the hidden genesis of retinitis pigmentosa by reporting new genetic mutations. In future, these advancements will help in better understanding the genotype-phenotype correlations of disease and likely to develop new therapies.
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38
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May-Simera H, Nagel-Wolfrum K, Wolfrum U. Cilia - The sensory antennae in the eye. Prog Retin Eye Res 2017; 60:144-180. [PMID: 28504201 DOI: 10.1016/j.preteyeres.2017.05.001] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 05/04/2017] [Accepted: 05/08/2017] [Indexed: 12/21/2022]
Abstract
Cilia are hair-like projections found on almost all cells in the human body. Originally believed to function merely in motility, the function of solitary non-motile (primary) cilia was long overlooked. Recent research has demonstrated that primary cilia function as signalling hubs that sense environmental cues and are pivotal for organ development and function, tissue hoemoestasis, and maintenance of human health. Cilia share a common anatomy and their diverse functional features are achieved by evolutionarily conserved functional modules, organized into sub-compartments. Defects in these functional modules are responsible for a rapidly growing list of human diseases collectively termed ciliopathies. Ocular pathogenesis is common in virtually all classes of syndromic ciliopathies, and disruptions in cilia genes have been found to be causative in a growing number of non-syndromic retinal dystrophies. This review will address what is currently known about cilia contribution to visual function. We will focus on the molecular and cellular functions of ciliary proteins and their role in the photoreceptor sensory cilia and their visual phenotypes. We also highlight other ciliated cell types in tissues of the eye (e.g. lens, RPE and Müller glia cells) discussing their possible contribution to disease progression. Progress in basic research on the cilia function in the eye is paving the way for therapeutic options for retinal ciliopathies. In the final section we describe the latest advancements in gene therapy, read-through of non-sense mutations and stem cell therapy, all being adopted to treat cilia dysfunction in the retina.
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Affiliation(s)
- Helen May-Simera
- Institute of Molecular Physiology, Cilia Biology, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Kerstin Nagel-Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany.
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Broadgate S, Yu J, Downes SM, Halford S. Unravelling the genetics of inherited retinal dystrophies: Past, present and future. Prog Retin Eye Res 2017; 59:53-96. [PMID: 28363849 DOI: 10.1016/j.preteyeres.2017.03.003] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 03/21/2017] [Accepted: 03/23/2017] [Indexed: 02/07/2023]
Abstract
The identification of the genes underlying monogenic diseases has been of interest to clinicians and scientists for many years. Using inherited retinal dystrophies as an example of monogenic disease we describe the history of molecular genetic techniques that have been pivotal in the discovery of disease causing genes. The methods that were developed in the 1970's and 80's are still in use today but have been refined and improved. These techniques enabled the concept of the Human Genome Project to be envisaged and ultimately realised. When the successful conclusion of the project was announced in 2003 many new tools and, as importantly, many collaborations had been developed that facilitated a rapid identification of disease genes. In the post-human genome project era advances in computing power and the clever use of the properties of DNA replication has allowed the development of next-generation sequencing technologies. These methods have revolutionised the identification of disease genes because for the first time there is no need to define the position of the gene in the genome. The use of next generation sequencing in a diagnostic setting has allowed many more patients with an inherited retinal dystrophy to obtain a molecular diagnosis for their disease. The identification of novel genes that have a role in the development or maintenance of retinal function is opening up avenues of research which will lead to the development of new pharmacological and gene therapy approaches. Neither of which can be used unless the defective gene and protein is known. The continued development of sequencing technologies also holds great promise for the advent of truly personalised medicine.
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Affiliation(s)
- Suzanne Broadgate
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Levels 5 and 6 West Wing, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK
| | - Jing Yu
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Levels 5 and 6 West Wing, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK
| | - Susan M Downes
- Oxford Eye Hospital, Oxford University Hospitals NHS Trust, Oxford, OX3 9DU, UK
| | - Stephanie Halford
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Levels 5 and 6 West Wing, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK.
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Nano M, Basto R. Consequences of Centrosome Dysfunction During Brain Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1002:19-45. [PMID: 28600781 DOI: 10.1007/978-3-319-57127-0_2] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Development requires cell proliferation, differentiation and spatial organization of daughter cells to occur in a highly controlled manner. The mode of cell division, the extent of proliferation and the spatial distribution of mitosis allow the formation of tissues of the right size and with the correct structural organization. All these aspects depend on cell cycle duration, correct chromosome segregation and spindle orientation. The centrosome, which is the main microtubule-organizing centre (MTOC) of animal cells, contributes to all these processes. As one of the most structurally complex organs in our body, the brain is particularly susceptible to centrosome dysfunction. Autosomal recessive primary microcephaly (MCPH), primordial dwarfism disease Seckel syndrome (SCKS) and microcephalic osteodysplastic primordial dwarfism type II (MOPD-II) are often connected to mutations in centrosomal genes. In this chapter, we discuss the consequences of centrosome dysfunction during development and how they can contribute to the etiology of human diseases.
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Affiliation(s)
- Maddalena Nano
- Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, 75005, Paris, France
| | - Renata Basto
- Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, 75005, Paris, France.
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Blanco-Sánchez B, Clément A, Phillips JB, Westerfield M. Zebrafish models of human eye and inner ear diseases. Methods Cell Biol 2016; 138:415-467. [PMID: 28129854 DOI: 10.1016/bs.mcb.2016.10.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Eye and inner ear diseases are the most common sensory impairments that greatly impact quality of life. Zebrafish have been intensively employed to understand the fundamental mechanisms underlying eye and inner ear development. The zebrafish visual and vestibulo-acoustic systems are very similar to these in humans, and although not yet mature, they are functional by 5days post-fertilization (dpf). In this chapter, we show how the zebrafish has significantly contributed to the field of biomedical research and how researchers, by establishing disease models and meticulously characterizing their phenotypes, have taken the first steps toward therapies. We review here models for (1) eye diseases, (2) ear diseases, and (3) syndromes affecting eye and/or ear. The use of new genome editing technologies and high-throughput screening systems should increase considerably the speed at which knowledge from zebrafish disease models is acquired, opening avenues for better diagnostics, treatments, and therapies.
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Affiliation(s)
| | - A Clément
- University of Oregon, Eugene, OR, United States
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42
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Abstract
The centrosome is the main microtubule organizing center of animal cells. It contributes to spindle assembly and orientation during mitosis and to ciliogenesis in interphase. Numerical and structural defects in this organelle are known to be associated with developmental disorders such as dwarfism and microcephaly, but only recently, the molecular mechanisms linking centrosome aberrations to altered physiology are being elucidated. Defects in centrosome number or structure have also been described in cancer. These opposite clinical outcomes--arising from reduced proliferation and overproliferation respectively--can be explained in light of the tissue- and developmental-specific requirements for centrosome functions. The pathological outcomes of centrosome deficiencies have become clearer when considering its consequences. Among them, there are genetic instability (mainly aneuploidy, a defect in chromosome number), defects in the symmetry of cell division (important for cell fate specification and tissue architecture) and impaired ciliogenesis. In this review, we discuss the origins and the consequences of centrosome flaws, with particular attention on how they contribute to developmental diseases.
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Affiliation(s)
- Maddalena Nano
- Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, 75005, Paris, France
| | - Renata Basto
- Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, 75005, Paris, France.
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Auer PL, Reiner AP, Wang G, Kang HM, Abecasis GR, Altshuler D, Bamshad MJ, Nickerson DA, Tracy RP, Rich SS, Leal SM, Leal SM. Guidelines for Large-Scale Sequence-Based Complex Trait Association Studies: Lessons Learned from the NHLBI Exome Sequencing Project. Am J Hum Genet 2016; 99:791-801. [PMID: 27666372 DOI: 10.1016/j.ajhg.2016.08.012] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 08/08/2016] [Indexed: 12/11/2022] Open
Abstract
Massively parallel whole-genome sequencing (WGS) data have ushered in a new era in human genetics. These data are now being used to understand the role of rare variants in complex traits and to advance the goals of precision medicine. The technological and computing advances that have enabled us to generate WGS data on thousands of individuals have also outpaced our ability to perform analyses in scientifically and statistically rigorous and thoughtful ways. The past several years have witnessed the application of whole-exome sequencing (WES) to complex traits and diseases. From our analysis of NHLBI Exome Sequencing Project (ESP) data, not only have a number of important disease and complex trait association findings emerged, but our collective experience offers some valuable lessons for WGS initiatives. These include caveats associated with generating automated pipelines for quality control and analysis of rare variants; the importance of studying minority populations; sample size requirements and efficient study designs for identifying rare-variant associations; and the significance of incidental findings in population-based genetic research. With the ESP as an example, we offer guidance and a framework on how to conduct a large-scale association study in the era of WGS.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Suzanne M Leal
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
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Farache D, Jauneau A, Chemin C, Chartrain M, Rémy MH, Merdes A, Haren L. Functional Analysis of γ-Tubulin Complex Proteins Indicates Specific Lateral Association via Their N-terminal Domains. J Biol Chem 2016; 291:23112-23125. [PMID: 27660388 DOI: 10.1074/jbc.m116.744862] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Indexed: 11/06/2022] Open
Abstract
Microtubules are nucleated from multiprotein complexes containing γ-tubulin and associated γ-tubulin complex proteins (GCPs). Small complexes (γTuSCs) comprise two molecules of γ-tubulin bound to the C-terminal domains of GCP2 and GCP3. γTuSCs associate laterally into helical structures, providing a structural template for microtubule nucleation. In most eukaryotes γTuSCs associate with additional GCPs (4, 5, and 6) to form the core of the so-called γ-tubulin ring complex (γTuRC). GCPs 2-6 constitute a family of homologous proteins. Previous structural analysis and modeling of GCPs suggest that all family members can potentially integrate into the helical structure. Here we provide experimental evidence for this model. Using chimeric proteins in which the N- and C-terminal domains of different GCPs are swapped, we show that the N-terminal domains define the functional identity of GCPs, whereas the C-terminal domains are exchangeable. FLIM-FRET experiments indicate that GCP4 and GCP5 associate laterally within the complex, and their interaction is mediated by their N-terminal domains as previously shown for γTuSCs. Our results suggest that all GCPs are incorporated into the helix via lateral interactions between their N-terminal domains, whereas the C-terminal domains mediate longitudinal interactions with γ-tubulin. Moreover, we show that binding to γ-tubulin is not essential for integrating into the helical complex.
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Affiliation(s)
- Dorian Farache
- From the Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France and
| | - Alain Jauneau
- Plateforme Imagerie-Microscopie, FR 3450 Pôle de Biotechnologie Végétale, 31326 Castanet-Tolosan, France
| | - Cécile Chemin
- From the Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France and
| | - Marine Chartrain
- From the Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France and
| | - Marie-Hélène Rémy
- From the Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France and
| | - Andreas Merdes
- From the Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France and
| | - Laurence Haren
- From the Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France and
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Novel compound heterozygous variants in PLK4 identified in a patient with autosomal recessive microcephaly and chorioretinopathy. Eur J Hum Genet 2016; 24:1702-1706. [PMID: 27650967 DOI: 10.1038/ejhg.2016.119] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 06/29/2016] [Accepted: 08/05/2016] [Indexed: 11/08/2022] Open
Abstract
It has been well documented that variants in genes encoding centrosomal proteins cause primary autosomal recessive microcephaly, although the association between centrosomal defects and the etiology of microcephaly syndromes is not fully understood. Polo-like kinase 4 (PLK4) is one of the centrosomal proteins required for centriole duplication. We here describe a patient with microcephaly and chorioretinopathy that harbors compound heterozygous missense variants, c.[442A>G]; [2336G>A], in the PLK4 gene. One of these variants, c.442A>G (p.(M148V)), resides in the kinase domain, and the other, c.2336G>A (p.(C779Y)), in the polo-box domain. Aberrant spindle formation was observed in a LCL derived from this patient. Overexpression experiments of the variant PLK4 proteins demonstrated that the p.(C779Y) but not the p.(M148V) had lost centriole overduplication ability. The altered mobility pattern of both variant proteins on a western blot further suggested alterations in post-translation modification. Our data lend support to the hypothesis that impaired centriole duplication caused by PLK4 variants may be involved in the etiology of microcephaly disorder.
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Lucchese G, Kanduc D. Zika virus and autoimmunity: From microcephaly to Guillain-Barré syndrome, and beyond. Autoimmun Rev 2016; 15:801-8. [DOI: 10.1016/j.autrev.2016.03.020] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 03/18/2016] [Indexed: 10/22/2022]
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Non-centrosomal nucleation mediated by augmin organizes microtubules in post-mitotic neurons and controls axonal microtubule polarity. Nat Commun 2016; 7:12187. [PMID: 27405868 PMCID: PMC4947180 DOI: 10.1038/ncomms12187] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 06/09/2016] [Indexed: 12/19/2022] Open
Abstract
Neurons display a highly polarized microtubule network that mediates trafficking throughout the extensive cytoplasm and is crucial for neuronal differentiation and function. In newborn migrating neurons, the microtubule network is organized by the centrosome. During neuron maturation, however, the centrosome gradually loses this activity, and how microtubules are organized in more mature neurons remains poorly understood. Here, we demonstrate that microtubule organization in post-mitotic neurons strongly depends on non-centrosomal nucleation mediated by augmin and by the nucleator γTuRC. Disruption of either complex not only reduces microtubule density but also microtubule bundling. These microtubule defects impair neurite formation, interfere with axon specification and growth, and disrupt axonal trafficking. In axons augmin does not merely mediate nucleation of microtubules but ensures their uniform plus end-out orientation. Thus, the augmin-γTuRC module, initially identified in mitotic cells, may be commonly used to generate and maintain microtubule configurations with specific polarity. In mature neurons the centrosome no longer functions as the main microtubule organizer and it is unclear how ordered microtubule arrays are assembled. Here, the authors show that in post-mitotic neurons this process depends on non-centrosomal nucleation mediated by the protein complex augmin and the nucleator gamma-TuRC.
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Bullerdiek J, Dotzauer A, Bauer I. The mitotic spindle: linking teratogenic effects of Zika virus with human genetics? Mol Cytogenet 2016; 9:32. [PMID: 27099632 PMCID: PMC4837584 DOI: 10.1186/s13039-016-0240-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 04/01/2016] [Indexed: 11/10/2022] Open
Abstract
Background Recently, an association between Zika virus infection and microcephaly/ocular findings was found to be reasonable e.g. because of the demonstration that the virus was found in the brain of a fetus after presumed maternal infection. Although there is no proof yet for a causal relationship, for an appropriate risk calculation efforts are urgently needed to either establish or disprove this assumption. Presentation of the hypothesis On the basis of inherited syndromes combining microcephaly with ocular findings similar to those associated with Zika infections, we have hypothesized that the impairment of the proper function of the mitotic apparatus is a possible mechanism by which Zika can exert teratogenic effects. Testing the hypothesis A bundle of well-known cytogenetic and molecular-cytogenetic methods (e.g. formation of micronuclei, chromosomal lagging, immunofluorescence of centrosomes) to evaluate proper function, maintenance, and establishment of the mitotic spindle poles can be applied on infected cells. Also, the viral proteins can be tested for their possible interaction with proteins encoded by genes involved in inherited syndromes with microcephaly and ocular findings resembling those in presumed cases of intrauterine ZIKV infection. Implications of the hypothesis Once proved, this hypothesis allows for a targeted approach into mechanisms of possible relevance as e.g. if different strains of the virus are implicated in the teratogenic effects to the same or a different extent.
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Affiliation(s)
- Joern Bullerdiek
- Centre for Human Genetics, University of Bremen, Leobener Str. ZHG, D-28359 Bremen, Germany ; Institute of Medical Genetics, University Rostock Medical Center, Ernst-Heydemann-Strasse 8, D-18057 Rostock, Germany
| | - Andreas Dotzauer
- Laboratory of Virus Research, University of Bremen, Leobener Straße/UFT, 28359, D-28359 Bremen, Germany
| | - Ingrid Bauer
- Institute of Medical Genetics, University Rostock Medical Center, Ernst-Heydemann-Strasse 8, D-18057 Rostock, Germany
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Cota RR, Teixidó-Travesa N, Ezquerra A, Eibes S, Lacasa C, Roig J, Lüders J. MZT1 regulates microtubule nucleation by linking γTuRC assembly to adapter-mediated targeting and activation. J Cell Sci 2016; 130:406-419. [DOI: 10.1242/jcs.195321] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 11/09/2016] [Indexed: 01/22/2023] Open
Abstract
Regulation of the γ-tubulin ring complex (γTuRC) through targeting and activation restricts nucleation of microtubules to microtubule organizing centers (MTOCs), aiding in the assembly of ordered microtubule arrays. However, the mechanistic basis of this important regulation remains poorly understood. Here we show that in human cells γTuRC integrity, determined by the presence of γ-tubulin complex proteins (GCPs) 2-6, is a prerequisite for interaction with the targeting factor NEDD1, impacting on essentially all γ-tubulin dependent functions. Recognition of γTuRC integrity is mediated by MZT1, which binds not only to the GCP3 subunit as previously shown, but cooperatively also to other GCPs through a conserved hydrophobic motif present in the N-termini of GCP2, GCP3, GCP5, and GCP6. MZT1 knockdown causes severe cellular defects under conditions that leave γTuRC intact, suggesting that the essential function of MZT1 is not in γTuRC assembly. Instead, MZT1 specifically binds fully assembled γTuRC to enable interaction with NEDD1 for targeting, and with the CM1 domain of CDK5RAP2 for stimulating nucleation activity. Thus, MZT1 is a ‘priming factor’ for the γTuRC that allows spatial regulation of nucleation.
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Affiliation(s)
- Rosa Ramírez Cota
- Institute for Research in Biomedicine (IRB Barcelona), 08028 Barcelona, Spain
| | | | - Artur Ezquerra
- Institute for Research in Biomedicine (IRB Barcelona), 08028 Barcelona, Spain
| | - Susana Eibes
- Institute for Research in Biomedicine (IRB Barcelona), 08028 Barcelona, Spain
| | - Cristina Lacasa
- Institute for Research in Biomedicine (IRB Barcelona), 08028 Barcelona, Spain
| | - Joan Roig
- Institute for Research in Biomedicine (IRB Barcelona), 08028 Barcelona, Spain
- Molecular Biology Institute of Barcelona (IBMB-CSIC), 08028 Barcelona, Spain
| | - Jens Lüders
- Institute for Research in Biomedicine (IRB Barcelona), 08028 Barcelona, Spain
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TUBA1A Mutation Associated With Eye Abnormalities in Addition to Brain Malformation. Pediatr Neurol 2015; 53:442-4. [PMID: 26294046 DOI: 10.1016/j.pediatrneurol.2015.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 07/09/2015] [Accepted: 07/11/2015] [Indexed: 01/10/2023]
Abstract
OBJECTIVE We describe the case of a boy with a TUBA1A mutation presenting with microphthalmia and congenital cataracts in addition to microcephaly and severe brain malformation. METHODS A boy presented in early infancy with microphthalmia, congenital cataracts, and microcephaly. His neurological course included severe hypotonia and drug-resistant epilepsy. Magnetic resonance imaging of the brain revealed a complex malformation that included agenesis of the corpus callosum, severely hypoplastic cerebellar vermis, mildly hypoplastic and dysplastic cerebellar hemispheres, mildly hypoplastic brainstem, mild posterior simplified cerebral gyral pattern, dysplastic basal ganglia and thalami, hypoplastic optic nerves, and absent olfactory bulbs. RESULTS TUBA1A genetic testing was conducted and revealed a previously unreported heterozygous 808G>T missense mutation. Parental genetic testing was negative, indicating that the child's mutation was de novo. CONCLUSION The TUBA1A gene encodes tubulin alpha-1A, a protein with an important role in microtubule function and stability. Human mutations can result in a wide spectrum of brain malformations including lissencephaly, microlissencephaly, cerebellar hypoplasia, agenesis of the corpus callosum, pachygyria and polymicrogyria. Although TUBA1A is expressed in both developing brain and retinal tissue, there are no reported cases of TUBA1A mutations in association with major developmental ophthalmologic abnormalities.
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